John'sscoreonthetestisthehighestintheclass;he____lastnight.
C
「句意」 约翰的考试分数全班最高;他昨天晚上一定学习了。
「难点」 表示对过去某一动作行为的猜测须要用must have done 这一句型结构。
.If you have really been studying English for so long, it’s about time you _____ able to write letters in English.
Under this（）pressure some of the rocks even became liquid.
Ifasubstanceisdissolvedinwaterorheated，itmay（）agas.
It’s high time we _____ cutting down the rainforests.