I ________ asleep because it took me a long time to realize that the telephone was ringing.　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

　 A. could fall        B. need have fallen     C. must have fallen 　    D. may fall

 I____ asleep because it took me a long time to realize that the telephone was ringing.

A. could have fallen      B. should have fallen  

C. must have fallen       D. mustn’t have fallen

I ________ asleep because it took me a long time to realize that the telephone was ringing.

1. A.
   could fall
2. B.
   need have fallen
3. C.
   must have fallen
4. D.
   may fall

I____ asleep because it took me a long time to realize that the telephone was ringing

1. A.
   could have fallen
2. B.
   should have fallen
3. C.
   must have fallen
4. D.
   mustn’t have fallen

 I____ asleep because it took me a long time to realize that the telephone was ringing.

A. could have fallen      B. should have fallen  

C. must have fallen       D. mustn’t have fallen