1.This is a good book.It's __D__.

A to read B.to see C.seeing D.reading

worth doing sth.Be worth doing shtg值得做某事。阅读要用read 所以答案选D

2.The headmaster made a great contribution ___A__ the new school.

A.to build B.to building C.built D.build

made a contribution to do 对......有贡献 这里的to是介词，而不是不定式的符号，所以很多人都误选了A。正确答案是B

3.We don't think Jim works hard,___B__?

A.doesn't he B.does he C.don't we D.do we

反意疑问句否定转移,原句相当于we think Jim doesn't work hard.后面要用肯定语气 答案选B。

4.The doctor ordered my sick grandfather to give up smoking.___A___.

A.So did he B.Neihter did he C.So he did D.Nor he did

句意是医生建议我生病的爷爷戒烟,爷爷那样做了.句型so+sb+助动词/情态动词表示某人的确做了某事

5._____ should I get Mary for her birthday?

A.How B.When C.Where D.What

根据情景才能确定答案，因为单纯就是题干，四个选项都正确，符合语法。这里不是虚拟语气。

6._____ can I get John a camera?

A.Where B.When C.How D.What

根据情景才能确定答案，因为单纯就是题干，四个选项都正确，符合语法。