请帮我分析并解答几道英语选择题

请帮我分析并解答几道英语选择题
1、 The two things __________ they felt very proud are Jim’s gold watch and Della’s hair.
A.about which B.of which C.in which D.for which
2、Ours is a beautiful school,________ we are proud.
A.about which B.of which C.in which D.for which
3、The astronaut did many experiments in the spaceship,__________ much help for knowing space.
A.which we think it is B.which we think are of
C.of which we think is D.I think which is of
4、The desk ________ which Jack is leaning is John’s.
A.in which B.on which C.against which
5、The dinner was the most expensive meal we __________.
A.would have B.have had C.had never had D.had ever had
6、 They were interested __________ you told them.
A.in which B.in that C.all that D.in everything
为何不能选C?
7、The great day we looked forward to __________ at last.
A.come B.came C.coming D.comes
8、 This is the only article of these that _____ written by him.
A.was B.were C.is D.are
请将每道题为什么选这个而不选那个的理由给我讲清楚好吗?
onliry只说了答案，并没有讲理由呀，哪位可以给讲讲理由啊，其实标准答案我有，只是不懂而已啊。