In man's early days, competition with other creatures must have been critical.
在人類早期，人類與其他生物的競爭一定是必不可少的。
新概念英語第四冊
Lesson 45 Of men and galaxies
?? 句中詞匯解析
從本句中提取的重要詞匯
n. 競爭;比賽;競爭者;[生]生存競爭;
?? compet=compete競爭+ition名詞后綴 →比賽，競爭
"He was astonished to learn he'd won the competition."
他聽說他比賽贏了，感到很驚訝。
近義：joust, match, meet, race, rivalry, tournament
反義：help, assist, assistance, relief, succor, succour
adj. 批評的，愛挑剔的;關鍵的;嚴重的;極重要的;
?? crit判斷，分辨+ical...的 → 批評的；危險的
"Now that the situation becomes critical, one must keep calm."
事到臨頭, 要沉住氣.
近義：key, momentous, significant, weighty, winning, watershed
反義：idle, immaterial, inane, inconsequential, inconsiderable, ineffective
adj. 早的;早期的;早日的;（果實等）早熟的;
adv. 早;在初期;先前;提早;
?? 三十“而立”（諧音），人生 早期
"They filed an application to have their case heard early."
他們申請早日審理他們的案子.
近義：onetime, back, previous, prior, old, earlier
反義：hind, hindmost, back, postern, puisne, retral
aux. 必須;必然要;（做出邏輯推斷）;（表示堅持）;
n. 必須做的事，必不可少的事物;葡萄汁;霉臭;麝香;
vt.& vi. （表示必要或很重要）必須;（提出建議）應該;得;（表示很可能或符合邏輯）一定;
adj. 不可或缺的;狂暴的;
"You must be able to speak French for this job."
干這項工作你得會說法語。
近義：ought, should, necessaries, necessity, precondition, prerequisite