6._____writer is better known in China，Charcles Dickens or Mark Twain?
A.Which B. What C. Either D. Whether
7. ---Have you seen Tom and Mary? ---I haven' t seen _____of them.
A.neither B. any C. either D. all
7.C【解析】前一句只提到两个人。neither，either，both仅用于表述两者的情况，而any，all表述多者的情况，且I haven't seen either of them相当于I have seen neither of them。
8.Is _____necessary to complete the design before National Day?
A.this B. that C. it D. he
9.All _____is needed is a supply of oil.
A.the thing B. that C. what D. which
9.B【解析】all是先行词，that 引导定语从句，且all that=what。
10.His camera is more expensive than ______.
A.hers B. her C. it D. its
10.A【解析】His camera是句子的主语，也是信息词，应填名词性的物主代词hers，它相当于her camera。