--- Who told you my address ?

--- I don’t remember clearly. It ______ Li Mei.
--- It ______ Li Mei. She doesn’t know it.

1. A.
   can be; mustn’t be
2. B.
   may have been;must have been
3. C.
   may have been; can’t be 　　　
4. D.
   must have been ; can’t have been

------ Who told you my address?

------ I don’t remember clearly. It ________ Li Mei.

------ It ________ Li Mei. She doesn’t know it.

A. can be; mustn’t be                                       B. may have been; must have been

C. may have been; can’t be                               D. must have been; can’t have been

--- Who told you my address ? --- I don't remember clearly. It _____ Li Mei.

　 ---It _____ Li Mei. She doesn't know it.

--- Who told you my address ? --- I don't remember clearly. It _____ Li Mei.

　 ---It _____ Li Mei. She doesn't know it.

　　A.can be; mustn't be 　　　　　 B.may have been;must have been

　　C.may have been; can't be 　　　      D.must have been ; can't have been

--- Who told you my address ? --- I don’t remember clearly. It _____ Li Mei.
　 ---It _____ Li Mei. She doesn’t know it.

--- Who told you my address ?

　 --- I don't remember clearly. It _____ Li Mei.

　 ---It _____ Li Mei. She doesn't know it.

　　A.can be; mustn't be 　　　　　　B.may have been;must have been

　　C.may have been; can't be 　　　 D.must have been ; can't have been