--A man answered the phone, I suppose it was her husband.

--It ____ her husband. He has been dead for ages.

1. A.
   mustn't be
2. B.
   mustn't have been
3. C.
   couldn't be
4. D.
   couldn't have been

 - A man answered the phone. I suppose it was her husband.
   - It ___ her husband. He has been dead for ages.
   A. mustn't be   B. couldn't have been   C. may not have been    D. mustn't have been

--A man answered the phone, I suppose it was her husband.

--It ____ her husband. He has been dead for ages.

[　　]

—It ________ her husband．He has been dead for ages.

A．mustn’t be

B．mustn’t have been

C．couldn’t be

D．couldn’t have been

—A man answered the phone. I suppose it was her husband.

—It ________ her husband．He has been dead for ages.

A．mustn’t be

B．mustn’t have been

C．couldn’t be

D．couldn’t have been