Their skin is very 39 to temperature changes. 40 warm weather, sweating helps humans regulate their body temperature.
答案：(C) sensitive
【句型】sensitive to 字詞搭配「對……敏感」；sensational（轟動的）、sensible（明智的）、sentimental（多愁善感的）都不搭配 temperature changes 這個語境。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個選項都是 sen- 開頭的形容詞，長得極像、中文卻天差地遠，是英文裡最經典的一組形近字。如果只憑「看起來很像敏感」去猜，很容易挑到 sensible。
先看空格後面接什麼：to temperature changes。後面有 to，而這四個字裡固定接 to 的是 sensitive：be sensitive to something（對某事敏感）。再用語意驗算：整段在講人體的自我保護機制，下一句說天氣溫暖時流汗可以幫忙調節體溫——皮膚要能對溫度變化起反應，前提就是它對溫度變化很敏感。所以填 sensitive。順便把這四個一次分清楚，它們常常一起出現在選項裡：sensitive（敏感的，接 to）、sensible（明智的、通情達理的）、sensational（轟動的、聳動的）、sentimental（多愁善感的）。
sensible（明智的）：講的是判斷力好，皮膚談不上明智；而且它接的是 of（It was sensible of you to ...）。sensational（轟動的、聳動的）：用來形容新聞或表演，與皮膚無關。sentimental（多愁善感的）：講的是情感豐富，也與溫度無關。
be sensitive to（對……敏感）、be sensible（明智的）、sensational news（轟動的新聞）、sentimental value（情感上的價值）、temperature changes（溫度變化）、regulate（調節）。
All forms of life have an instinctive urge to survive. Nature provides 31 with the means of survival. We have learned much about survival from 32 forms of animal life.
Lizards, 33 can change the color of their skin and 34 the trees and leaves around them. 35 , they cannot be detected by other animals that threaten them. Nature provides other forms of protection 36 environmental dangers.
Human beings, too, 37 special devices to protect 38 . Their skin is very 39 to temperature changes. 40 warm weather, sweating helps humans regulate their body temperature.