幾題文法題請教 - 英檢

有些問題想請教一下板上的大大
1. ______, all machines are combinations of simpler machines such as the
lever, the pulley, and the inclined plane.
(A) How complex is not a matter of (B) The matter is complex if no
(C) It does not matter if the complexity (D) No matter how complex

答案是D 但是我不太清楚 這題是在考甚麼觀念?

15. The green turtle has been known ______ over 2,000 miles to return to a
nesting site.
(A) in the navigating (B) the navigation (C) to navigate (D)
navigation

答案是C 但是我選A 我不太懂考試時該如何準備像這一類的慣用語?
似乎有背到才會 沒背到就掛了

文法改錯

31. A drum is constructed {by stretching} a membrane of skin or
A
velum {across} one or {both} end of {an open} cylinder.
B C D
答案是C 我選D 我不知道C錯在哪裡?

36. Games and recreation provide a release {from} tension and {make} people
A B
{both} more willing and {fittingly} to resume their daily routines.
C D

答案是D 但是我想請問一下如果把C both拿掉 語意是否還說得通?

以上是我的問題 如果有冒犯的地方 請大家包涵 謝謝大家

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