16. Our students are free to study _____ interests them.
A. that B. whichever C. whatever D. anything
答案： C
解析： 我们的学生有自由学习自已所感兴趣的东西。
17. Mathematics _____ easy to learn.
A. is B. are C. can D. feels
答案：A
解析： 数学是很容易学习的。这里注意这个单词Mathematics，是一门学科，谓语要用单数形式。
18. It’s never _____ .
A. late enough to learn B. not late enough to learn
C. too late to learn D. so late as not learn
答案： C
解析：活到老，学到老。too……to…… 太……而不能……, 这是一个否定句式，注意句子中有一个never，否定含义，双重否定，所以这个句子为肯定的语气。
19. I don’t know whether he is still _____ in collecting coins. He used to be, but that was several years ago.
A. interested B. interesting
C. interest D. disinterested
答案：A
解析： 我不知道他是否还对收集古币感兴趣。他过去是这样的，但这是几年前了。短语be interested in doing… 对…感兴趣。
20. The noise outside was _____.
A. too irritating that
B. so irritating so his speech was hardly audible
C. so irritating that his speech was hardly audible
D. so irritating enough that his speech was hardly audible
答案：C
解析：外面的嘈杂声是如此地令人厌烦，以至于很难听清他的演讲。 So…that… 如此…以至于… ； audible听得见的； irritating 让人气愤的，让人厌烦的。