我问了我的朋友，她是IELTS的考官，她答复我：
11. ---You seem to like sweets.
---_____ .That’s probably why I’m becoming fatter and fatter.
A. So I do                B.        So do I                C.        So am I          D. So I am   
应该选B，Here 'so' is referring back to 'liking sweets'. Another example 'you seem to like chocolate, so do I' (meaning I also like chocolate)


21. Mom, I’v got a fever.
    --- So _____ . How did you catch ti?
A.        have you                B.        you have                C.        have I                D. did I
应该选B，It's a confirmation, meaning 'yes, this is true, you do have a fever'. (perhaps she put a hand on her son's forehead to confirm that he has a fever). Another example, 'I think it's a holiday on February 14' 'So it is!' (after checking my diary)..

LZ的题目很好啊,顺便复习一下很久不用的语法了.

78题,D (quite a few)为什么不可以?
其他的同意你的答案!.

谢谢.