• 一日いちにち
  • ·one day
  • ·all day (long); the whole day; from morning till night
  • ·first day of the month
  N5
• 八はち
  • ·eight; 8
  N5
• 時間じかん
  • ·time
  • ·hour
  • ·period; class; lesson
  N5
• 言ういう
  • ·to say; to utter; to declare
  • ·to name; to call
  • ·to go (e.g. "the alarm went ping"); to make a noise
  N5
• 人ひと
  • ·person; someone; somebody
  • ·human beings; mankind; man; people; humans
  • ·human (Homo sapiens)
  • ·(other) people; others
  • ·character; personality; nature
  • ·capable person; competent person; suitable person; right person
  • ·adult; grown-up
  • ·I; me; one
  N5
• いる
  • ·to be (of animate objects); to exist
  • ·to stay
  • ·to be ...-ing
  • ·to have ...-ed; to be ...-ed
  N5
• それ
  • ·that; it
  • ·then; that point (in time); that time
  • ·there
  • ·you
  N5
• ある
  • ·to be; to exist; to live
  • ·to have
  • ·to be located
  • ·to be equipped with
  • ·to happen; to come about
  • ·to exist (in a completed state); to be (something unchanged in its current state)
  N5
• するAs it appears here: させ
  • ·to do; to carry out; to perform
  • ·to cause to become; to make (into); to turn (into)
  • ·to serve as; to act as; to work as
  • ·to wear (clothes, a facial expression, etc.)
  • ·to judge as being; to view as being; to think of as; to treat as; to use as
  • ·to decide on; to choose
  • ·to be sensed (of a smell, noise, etc.)
  • ·to be (in a state, condition, etc.)
  • ·to be worth; to cost
  • ·to pass (of time); to elapse
  • ·to place, or raise, person A to a post or status B
  • ·to transform A to B; to make A into B; to exchange A for B
  • ·to make use of A for B; to view A as B; to handle A as if it were B
  • ·to feel A about B
  • ·verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs")
  • ·creates a humble verb (after a noun prefixed with "o" or "go")
  • ·to be just about to; to be just starting to; to try to; to attempt to
  N5
• よく
  • ·nicely; properly; well; skillfully; skilfully
  • ·frequently; often
  • ·I'm glad that you ...; thank you for ...
  • ·(you have) quite the nerve to; I don't know how you can ...
  N5
• するAs it appears here: させる
  • ·to do; to carry out; to perform
  • ·to cause to become; to make (into); to turn (into)
  • ·to serve as; to act as; to work as
  • ·to wear (clothes, a facial expression, etc.)
  • ·to judge as being; to view as being; to think of as; to treat as; to use as
  • ·to decide on; to choose
  • ·to be sensed (of a smell, noise, etc.)
  • ·to be (in a state, condition, etc.)
  • ·to be worth; to cost
  • ·to pass (of time); to elapse
  • ·to place, or raise, person A to a post or status B
  • ·to transform A to B; to make A into B; to exchange A for B
  • ·to make use of A for B; to view A as B; to handle A as if it were B
  • ·to feel A about B
  • ·verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs")
  • ·creates a humble verb (after a noun prefixed with "o" or "go")
  • ·to be just about to; to be just starting to; to try to; to attempt to
  N5
• できる
  • ·to be able to do; to be possible; to be permitted (to do)
  • ·to be good at; to do well; to be proficient (in); to be capable
  • ·to come into existence; to form; to appear; to come up (of a matter); to be born; to make (a friend); to get (a girlfriend, free time, etc.)
  • ·to be made; to be built; to be constructed; to be formed; to be established; to be set up
  • ·to be finished; to be completed; to be done; to be ready
  • ·to grow (of a crop); to be produced
  • ·to be mature and well-balanced; to be of fine character
  • ·to be by nature; to be born ...
  • ·to become (sexually) involved (with); to become intimate (with); to take up (with someone)
  • ·to get pregnant
  N5
• いくAs it appears here: いかない
  • ·to go; to move (towards); to head (towards); to leave (for)
  • ·to move through; to travel across; to walk along (e.g. a road)
  • ·to go (well, badly, etc.); to proceed; to turn out; to get along
  • ·to do (in a particular way); to go (with; a choice); to try
  • ·to pass (of time, seasons, etc.); to go by
  • ·to stream; to flow
  • ·to die; to pass away
  • ·to reach (a stage, extent, age, etc.); to get to; to go (so far as ...)
  • ·to reach (of information, instructions, wind, etc.); to arrive
  • ·to continue ...; to go on ...; to (progress) steadily; to gradually ...; to progressively ...
  • ·to have an orgasm; to come; to cum
  • ·to trip; to get high; to have a drug-induced hallucination
  N5
• また
  • ·again; once more; once again; another time; some other time
  • ·also; too; as well; likewise
  • ·on the other hand; while
  • ·and; in addition; besides; moreover; furthermore
  • ·or; otherwise
  • ·really; how; (what, why) on earth
  • ·some time (in the future)
  • ·indirect
  N5
• するAs it appears here: して
  • ·to do; to carry out; to perform
  • ·to cause to become; to make (into); to turn (into)
  • ·to serve as; to act as; to work as
  • ·to wear (clothes, a facial expression, etc.)
  • ·to judge as being; to view as being; to think of as; to treat as; to use as
  • ·to decide on; to choose
  • ·to be sensed (of a smell, noise, etc.)
  • ·to be (in a state, condition, etc.)
  • ·to be worth; to cost
  • ·to pass (of time); to elapse
  • ·to place, or raise, person A to a post or status B
  • ·to transform A to B; to make A into B; to exchange A for B
  • ·to make use of A for B; to view A as B; to handle A as if it were B
  • ·to feel A about B
  • ·verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs")
  • ·creates a humble verb (after a noun prefixed with "o" or "go")
  • ·to be just about to; to be just starting to; to try to; to attempt to
  N5
• ほか
  • ·another place; some other place; somewhere else; outside
  • ·another (person or thing); other; different; something else; someone else; the rest; et al.
  • ·beyond (one's expectations, imagination, etc.); outside
  • ·except; but; other than; apart from
  • ·besides; in addition to; as well as; on top of
  N5
• そちら
  • ·that way; that direction
  • ·there
  • ·that (one)
  • ·you; your family; your company
  • ·that person
  N5
• なる
  • ·to become; to get; to grow; to turn; to reach; to attain
  • ·to result in; to turn out; to end up; to prove (to be)
  • ·to consist of; to be composed of; to be made up of
  • ·to be completed; to be realized; to succeed; to be attained; to be accomplished
  • ·to change (into); to turn (into); to transform
  • ·to come (to do); to begin (to do); to grow (to do)
  • ·to come to; to amount to; to add up to; to make
  • ·to play (the part of); to act as
  • ·to be used for; to be useful for; to serve as
  • ·to be promoted
  • ·to do ...
  N5
• もの
  • ·thing; object; article; stuff; substance
  • ·one's things; possessions; property; belongings
  • ·things; something; anything; everything; nothing
  • ·quality
  • ·reason; the way of things
  • ·used to emphasize emotion, judgment, etc.; used to indicate a common occurrence in the past (after a verb in past tense); used to indicate a general tendency; used to indicate something that should happen
  • ·item classified as ...; item related to ...; work in the genre of ...
  • ·cause of ...; cause for ...
  • ·somehow; somewhat; for some reason
  • ·really; truly
  N5
• なるAs it appears here: なって
  • ·to become; to get; to grow; to turn; to reach; to attain
  • ·to result in; to turn out; to end up; to prove (to be)
  • ·to consist of; to be composed of; to be made up of
  • ·to be completed; to be realized; to succeed; to be attained; to be accomplished
  • ·to change (into); to turn (into); to transform
  • ·to come (to do); to begin (to do); to grow (to do)
  • ·to come to; to amount to; to add up to; to make
  • ·to play (the part of); to act as
  • ·to be used for; to be useful for; to serve as
  • ·to be promoted
  • ·to do ...
  N5
• しかし
  • ·however; but
  N5
• するAs it appears here: した
  • ·to do; to carry out; to perform
  • ·to cause to become; to make (into); to turn (into)
  • ·to serve as; to act as; to work as
  • ·to wear (clothes, a facial expression, etc.)
  • ·to judge as being; to view as being; to think of as; to treat as; to use as
  • ·to decide on; to choose
  • ·to be sensed (of a smell, noise, etc.)
  • ·to be (in a state, condition, etc.)
  • ·to be worth; to cost
  • ·to pass (of time); to elapse
  • ·to place, or raise, person A to a post or status B
  • ·to transform A to B; to make A into B; to exchange A for B
  • ·to make use of A for B; to view A as B; to handle A as if it were B
  • ·to feel A about B
  • ·verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs")
  • ·creates a humble verb (after a noun prefixed with "o" or "go")
  • ·to be just about to; to be just starting to; to try to; to attempt to
  N5
• 持つもつ
  • ·to hold (in one's hand); to take; to carry
  • ·to possess; to have; to own
  • ·to maintain; to keep
  • ·to last; to be durable; to keep; to survive
  • ·to take charge of; to be in charge of
  • ·to hold (meeting, etc.); to have (opportunity, etc.)
  • ·to have "it"; to have that special something; to be blessed with good luck
  N5
• 大人おとな
  • ·adult; grown-up
  N5
• 寝るねる
  • ·to sleep (lying down)
  • ·to go to bed; to lie in bed
  • ·to lie down
  • ·to sleep (with someone, i.e. have intercourse)
  • ·to lie flat (e.g. of hair)
  • ·to lie idle (of funds, stock, etc.)
  • ·to ferment (of soy sauce, miso, etc.)
  N5
• ここ
  • ·here; this place
  • ·this point; here; now
  • ·these past ... (e.g. three years); these last ...
  • ·the next ... (e.g. few days); these next ...
  N5
• するAs it appears here: せよ
  • ·to do; to carry out; to perform
  • ·to cause to become; to make (into); to turn (into)
  • ·to serve as; to act as; to work as
  • ·to wear (clothes, a facial expression, etc.)
  • ·to judge as being; to view as being; to think of as; to treat as; to use as
  • ·to decide on; to choose
  • ·to be sensed (of a smell, noise, etc.)
  • ·to be (in a state, condition, etc.)
  • ·to be worth; to cost
  • ·to pass (of time); to elapse
  • ·to place, or raise, person A to a post or status B
  • ·to transform A to B; to make A into B; to exchange A for B
  • ·to make use of A for B; to view A as B; to handle A as if it were B
  • ·to feel A about B
  • ·verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs")
  • ·creates a humble verb (after a noun prefixed with "o" or "go")
  • ·to be just about to; to be just starting to; to try to; to attempt to
  N5
• この
  • ·this
  • ·last (couple of years, etc.); these; past; this
  • ·you (as in "you liar")
  N5
• 今日きょう
  • ·today; this day
  • ·these days; recently; nowadays
  N5
• 本ほん
  • ·book; volume; script
  • ·this; present; current; ... in question; ... at issue
  • ·main; head; principal
  • ·real; genuine; regular; proper
  • ·counter for long, thin objects (sticks, tubes, strings, bottles, pillars, rivers, rail lines, etc.)
  • ·counter for films, TV shows, etc.
  • ·counter for telephone calls, letters, and emails
  • ·counter for goals, home runs, etc.
  • ·counter for rounds or points (in judo, kendo, etc.)
  N5
• 眠るねむる
  • ·to sleep
  • ·to die; to rest (in peace); to lie (buried); to sleep (in the grave)
  • ·to lie idle (e.g. of resources); to lie unused; to lie untapped; to lie untouched
  • ·to close one's eyes
  N4
• 特別とくべつ
  • ·special; particular; extraordinary; exceptional; especial
  N4
• ため
  • ·good; advantage; benefit; welfare
  • ·sake; purpose; objective; aim
  • ·consequence; result; effect
  • ·affecting; regarding; concerning
  N4
• 技術ぎじゅつ
  • ·technology; engineering
  • ·technique; skill
  • ·art; craft
  N4
• 無理むり
  • ·unreasonable; unnatural; unjustifiable
  • ·impossible
  • ·forcible; forced; compulsory
  • ·excessive (work, etc.); immoderate
  • ·to work too hard; to try too hard
  • ·no way; not a chance; never; dream on
  • ·irrational
  N4
• はず
  • ·should (be); bound (to be); expected (to be); must (be)
  • ·nock (of a bow)
  • ·nock (of an arrow)
  • ·nock-shaped grip (between thumb and forefinger)
  • ·wooden frame on the tip of the mast of a Japanese ship that prevents the hawser from falling out
  N4
• 下げるさげる
  • ·to hang; to suspend; to wear (e.g. decoration)
  • ·to lower; to reduce; to bring down
  • ·to demote; to move back; to pull back
  • ·to clear (plates); to remove (food, etc. from table or altar)
  • ·to keep on playing after one has formed a scoring combination with captured cards
  N4
• 危険きけん
  • ·danger; peril; hazard
  • ·risk
  N4
• 安全あんぜん
  • ·safety; security
  N4
• わけ
  • ·reason; cause; grounds
  • ·meaning; sense
  • ·(good) sense; reason
  • ·circumstances; case
  • ·(romantic) relationship; love affair
  N4
• 安心あんしん
  • ·peace of mind; relief; (sense of) security; safety; assurance; confidence
  N4
• うち
  • ·inside; within
  • ·while (e.g. one is young); during; within (e.g. a day); in the course of
  • ·among; amongst; (out) of; between
  • ·in (secret, chaos, poverty, etc.); amidst; with (e.g. success)
  • ·within oneself; one's feelings; inner thoughts
  • ·we; our company; our organization
  • ·one's home; one's family
  • ·my spouse; my husband; my wife
  • ·signed on behalf of (husband's name) by his wife
  • ·I; me
  • ·imperial palace grounds
  • ·emperor
  N4
• 眠るねむるAs it appears here: 眠り
  • ·to sleep
  • ·to die; to rest (in peace); to lie (buried); to sleep (in the grave)
  • ·to lie idle (e.g. of resources); to lie unused; to lie untapped; to lie untouched
  • ·to close one's eyes
  N4
• 規則きそく
  • ·rule; regulation
  N4
• 季節きせつ
  • ·season; time of year
  N4
• 考えるかんがえる
  • ·to think (about, of); to think over; to ponder; to contemplate; to reflect (on); to meditate (on)
  • ·to consider; to bear in mind; to allow for; to take into consideration
  • ·to think (that); to believe; to hold (a view); to judge; to conclude; to suspect
  • ·to intend (to do); to think of (doing); to plan
  • ·to predict; to anticipate; to expect; to imagine
  • ·to come up with; to think up; to contrive; to devise
  • ·to consider (as); to regard (as); to look on (as); to take; to view
  N4
• よう
  • ·appearing ...; looking ...
  • ·way to ...; method of ...ing
  • ·form; style; design
  • ·like; similar to
  • ·thing (thought or spoken)
  N3
• 何かなにか
  • ·something; some; any
  • ·somehow; for some reason
  • ·(so) what (are you trying to say)?; what (do you mean)?
  N3
• 睡眠すいみん
  • ·sleep
  N3
• さまざま
  • ·various; varied; diverse; all sorts of
  N3
• 身体しんたい
  • ·body; physical system; (the) person
  N3
• 合わせるあわせるAs it appears here: 合わせて
  • ·to match (rhythm, speed, etc.)
  • ·to join together; to unite; to combine; to add up
  • ·to face; to be opposite (someone)
  • ·to compare; to check with
  • ·to cause to meet (e.g. an unpleasant fate)
  • ·to place together; to connect; to overlap
  • ·to mix; to combine
  • ·to put blade to blade; to fight
  N3
• うまいAs it appears here: うまく
  • ·skillful; skilful; skilled; good; expert; clever (expression, trick, etc.); apt; appropriate
  • ·delicious; tasty; good; nice
  • ·good (deal, idea, etc.); profitable; promising; lucky; fortunate; successful; satisfactory; splendid
  N3
• 活動かつどう
  • ·activity (of a person, organization, animal, volcano, etc.); action; operation
  • ·moving picture
  N3
• 多少たしょう
  • ·a little; some; somewhat; slightly; to some degree; to some extent
  • ·amount; quantity; number
  N3
• しかも
  • ·moreover; furthermore
  • ·nevertheless; and yet
  N3
• こと
  • ·thing; matter
  • ·incident; occurrence; event; something serious; trouble; crisis
  • ·circumstances; situation; state of affairs
  • ·work; business; affair
  • ·after an inflectable word, creates a noun phrase indicating something the speaker does not feel close to
  • ·nominalizing suffix
  • ·pretending to ...; playing make-believe ...
  • ·alias; also known as; otherwise known as; or
  • ·necessity; need
  • ·you should ...; I advise that you ...; it's important to ...
  N3
• 筋肉きんにく
  • ·muscle
  N3
• 意識いしき
  • ·consciousness
  • ·becoming aware (of); awareness; sense
  • ·mano-vijnana (mental consciousness, cognizer of sensory information)
  N3
• 中ちゅう
  • ·medium (size); average (grade, level, etc.); middle
  • ·in; within; out of (e.g. ten people); among
  • ·during; while; in (the course of); within (a period); throughout
  • ·currently (doing); in the process of; in the middle of; under (e.g. construction, investigation)
  • ·middle way; moderation
  • ·second volume (of three)
  • ·junior high school; middle school
  • ·China
  N3
• 条件じょうけん
  • ·condition; term; requirement; qualification; prerequisite
  N3
• 生き物いきもの
  • ·living thing; living creature; animal; life
  N3
• 譲るゆずる
  • ·to hand over; to transfer; to turn over; to assign; to convey; to bequeath
  • ·to give up (e.g. one's seat); to give way
  • ·to yield; to concede; to give ground; to surrender
  • ·to sell
  • ·to postpone; to put off; to defer
  N3
• かぎるAs it appears here: かぎられた
  • ·to restrict; to limit; to confine
  • ·to be restricted to; to be limited to; to be confined to
  • ·to be best (for); to be the best plan; to be the only way (to)
  N3
• もと
  • ·origin; source; beginning
  • ·basis; base; foundation; root
  • ·cause
  • ·(raw) material; ingredient; base; mix (e.g. for a cake); (soup) stock
  • ·(one's) side
  • ·capital; principal; cost price
  • ·root (of a plant); (tree) trunk
  • ·part (of a brush, chopsticks, etc.) one holds (with the hand)
  • ·first three lines of a waka
  • ·counter for plants or trees
  • ·counter for falcons (in falconry)
  N3
• 人間にんげん
  • ·human being; human; person; man; mankind; humankind
  • ·character (of a person)
  N3
• まったく
  • ·really; truly; entirely; completely; wholly; perfectly
  • ·indeed
  • ·good grief
  N3
• 同様どうよう
  • ·same; similar; (just) like; equal
  N3
• 備えるそなえるAs it appears here: 備えて
  • ·to furnish with; to equip with; to provide; to install
  • ·to prepare for; to make preparations for; to make provision for
  • ·to possess (all that is needed); to be endowed with; to be equipped with
  • ·to be born with; to have since birth
  N3
• 文明ぶんめい
  • ·civilization; civilisation; culture
  • ·Bunmei era (1469.4.28-1487.7.20)
  N3
• 発達はったつ
  • ·development; growth
  • ·progress; development; advancement
  • ·expansion (of a typhoon, low-pressure area, etc.)
  • ·developmental disability; person with a developmental disability
  N3
• 変化へんか
  • ·change; variation; alteration; mutation; transition; transformation
  • ·variety; diversity
  • ·inflection; declension; conjugation
  • ·henka; (expl.) evasive sidestep at the beginning of a bout
  N3
• 世の中よのなか
  • ·society; the world; the times
  N3
• 傾向けいこう
  • ·tendency; trend; inclination
  N3
• 不幸ふこう
  • ·unhappiness; sorrow; misfortune; disaster; accident
  • ·death (usu. of a relative); bereavement
  N3
• 過ごすすごす
  • ·to spend (time); to pass; to lead (a life); to live
  • ·to overdo (esp. alcohol consumption); to drink (alcohol); to carry too far; to carry to excess
  • ·to take care of; to support
  • ·to overdo; to do too much
  • ·to ... without acting on it; to ... without getting involved
  N3
• 大半たいはん
  • ·majority; more than half; most (of)
  • ·mostly; largely; mainly; predominately; nearly
  N3
• 占めるしめる
  • ·to account for; to make up; to take up
  • ·to occupy (a place, position, etc.); to hold (a rank, seat, etc.)
  • ·to occupy (one's mind, heart, etc.); to weigh (on one's mind); to grip (e.g. one's heart)
  • ·to gain; to secure; to obtain; to win
  N3
• もともと
  • ·originally; from the start; from the beginning; from the outset; by nature
  • ·none the worse (for); (coming out) even; in the same position (as before)
  N2
• 外部がいぶ
  • ·outside (e.g. of a building); exterior
  • ·outside (of a group, company, etc.); outside world
  N2
• 休息きゅうそく
  • ·rest; relief; relaxation
  N2
• なす
  • ·to do; to commit; to carry out; to bring about
  N2
• 過程かてい
  • ·process; course; mechanism
  N2
• 本来ほんらい
  • ·originally; primarily
  • ·essentially; intrinsically; naturally; by nature; in (and of) itself
  • ·proper; rightful; legal; normal
  N2
• 一定いってい
  • ·to fix; to settle; to standardize; to regularize
  • ·constant; definite; uniform; defined; certain; prescribed
  N2
• こうして
  • ·thus; in this way
  N2
• まとめるAs it appears here: まとめて
  • ·to collect; to put (it all) together; to integrate; to consolidate; to unify
  • ·to summarize; to aggregate
  • ·to bring to a conclusion; to finalize; to settle; to put in order
  • ·to establish; to decide
  N2
• 基準きじゅん
  • ·standard; criterion; norm; benchmark; measure; gauge; basis
  N2

Example sentences are translated by AI.

• かのようにN22 times in this passage

  Likens a situation to something known to be contrary to fact — 'as if / as though'.

  一日に八時間眠るのが人間社会の決まりごとであるかのように言う人がいる。

  Some people speak as though sleeping eight hours a day were a rule of human society.

• しかもN2

  Additive conjunction adding a further, often stronger point — 'moreover, and what's more'.

  しかも、眠ることは筋肉を緩ませる、意識レベルを下げる、栄養補給を断つなどの危険を伴う「命懸け」の行為だ。

  Moreover, sleeping is a “life-risking” act involving dangers such as relaxing the muscles, lowering the level of consciousness, and interrupting nutritional intake.

• てからでないとN2

  Marks one action as a precondition for another — "unless/until you first do X, you can't do Y."

  それだけに、睡眠中の安全が確保できる条件を整えてからでないと、眠るわけにいかないというのが生き物の鉄則だ。

  For that very reason, a fundamental rule for living creatures is that they cannot sleep until conditions ensuring safety during sleep have been established.

• の下でN2

  under the supervision, conditions, or influence of ~ — 'under ~', 'based on ~'

  一日のうちのかぎられた条件と時間のもとでうまく眠り、うまく目覚めるために、高等動物は進化の過程でさまざまな方式を開発してきた。

  In order to sleep and wake effectively within the limited conditions and time available in a day, higher animals have developed various methods over the course of evolution.

• をもとにN2

  Marks the source material or foundation something is created or judged from — "based on ~; on the basis of ~".

  社会活動や季節変化などをもとにして、睡眠の持つ多様性を一定の枠の中に押し込めてしまったのだ。

  Based on factors such as social activity and seasonal changes, people have forced the natural diversity of sleep into a fixed framework.

• にせよ／にしろN2

  Concedes that whatever the case named, the main point still holds; 'even if / whether ... or / in any case'.

  一日に八時間くらい寝床の中で過ごす人が大半を占めるにせよ、この数値に生物学的な根拠はない。

  Even if most people spend around eight hours a day in bed, this figure has no biological basis.

• ためにN33 times in this passage

  marks a purpose ('in order to') or a cause ('because of / owing to').

  もともと睡眠は、適応のための技術である。

  Sleep is originally a technique for adaptation.

• というN32 times in this passage

  Quotative marker plus 'say' that introduces a name, definition, or reported content — 'called', 'known as', 'that (one) says'.

  それだけに、睡眠中の安全が確保できる条件を整えてからでないと、眠るわけにいかないというのが生き物の鉄則だ。

  For that very reason, a fundamental rule for living creatures is that they cannot sleep until conditions ensuring safety during sleep have been established.

• と共に（とともに）N3

  Links two things that happen together or change at the same time — "together with; along with; as ~ does".

  しかし、人間は文明の発達とともに、睡眠を人為的な規則で拘束した。

  However, with the development of civilization, humans have constrained sleep with artificial rules.

• 的（てき）N32 times in this passage

  A suffix turning a noun into a na-adjective meaning "relating to / -like / -ical" (一般的, 科学的).

  しかし、人間は文明の発達とともに、睡眠を人為的な規則で拘束した。

  However, with the development of civilization, humans have constrained sleep with artificial rules.

• によって/によるN3

  Marks means, cause, passive agent, or a factor something depends on; 'by (means of)', 'due to', 'depending on'.

  （井上昌次郎『睡眠の技術――今日からぐっすり眠れる本』による）

  (Based on Inoue Shoujirou, “The Technique of Sleep — A Book for Sleeping Soundly Starting Today”)

• よりN4

  Particle marking the standard in a comparison (also a starting point), "than / (more) than; from".

  さまざまな身体内部および外部の環境条件に合わせて、脳をうまく休息させ、よりよく活動させるための柔軟な生存戦略である。

  It is a flexible survival strategy for resting the brain appropriately and enabling it to function better in response to various internal and external environmental conditions.

• させるN4

  Causative construction — make or let someone do an action ('make/let ~ do').

  さまざまな身体内部および外部の環境条件に合わせて、脳をうまく休息させ、よりよく活動させるための柔軟な生存戦略である。

  It is a flexible survival strategy for resting the brain appropriately and enabling it to function better in response to various internal and external environmental conditions.

• はずがないN4

  Expresses strong conviction that something is impossible or cannot be true — 'there's no way, couldn't possibly'.

  多少の無理や融通が利かないはずはない。

  It cannot possibly be so inflexible that it allows no strain or adjustment at all.

• などN42 times in this passage

  Lists one or more representative items and implies others of the same kind exist — 'and so on / etc. / such as'.

  しかも、眠ることは筋肉を緩ませる、意識レベルを下げる、栄養補給を断つなどの危険を伴う「命懸け」の行為だ。

  Moreover, sleeping is a “life-risking” act involving dangers such as relaxing the muscles, lowering the level of consciousness, and interrupting nutritional intake.

• 〜てしまう / 〜ちゃうN42 times in this passage

  Verb te-form plus しまう, marking an action as fully completed or done regrettably/by accident — 'end up ...ing' / 'finish ...ing'; ちゃう/じゃう is the casual contraction.

  そうなると、安心して睡眠に割り当てられる時間は、かなりかぎられたものになってしまう。

  As a result, the amount of time that can safely be devoted to sleep becomes quite limited.

• 〜てくるN4

  Verb te-form plus 来る, marking motion toward the speaker or the gradual onset of a state — 'come to do' / 'start to / become'.

  一日のうちのかぎられた条件と時間のもとでうまく眠り、うまく目覚めるために、高等動物は進化の過程でさまざまな方式を開発してきた。

  In order to sleep and wake effectively within the limited conditions and time available in a day, higher animals have developed various methods over the course of evolution.

• 〜の中でN4

  Marks a set or group as the domain of a comparison — "among ~ / of all ~", typically paired with a superlative.

  一日に八時間くらい寝床の中で過ごす人が大半を占めるにせよ、この数値に生物学的な根拠はない。

  Even if most people spend around eight hours a day in bed, this figure has no biological basis.

• がありますN5

  States the existence or possession of an inanimate thing, "there is / to have".

  それには何か特別な根拠があるのか。

  Is there any particular basis for that?

• 〜ているN5

  Describes an action in progress or the state that remains after an action happened — “is doing” or “is in the state of having done”.

  人間の睡眠も、生物学的にはまったく同様の適応力を備えている。

  Biologically, human sleep possesses exactly the same kind of adaptability.

• しかしN5

  Contrastive conjunction joining two sentences, 'however / but'.

  しかし、人間は文明の発達とともに、睡眠を人為的な規則で拘束した。

  However, with the development of civilization, humans have constrained sleep with artificial rules.

• にするN5

  To decide on or turn something into a given state or choice, 'to make it ~ / to go with ~.'

  ここから、睡眠時間の負債を気にするという不幸が発生したのだ。

  From this arose the unfortunate habit of worrying about a “sleep-time debt.”