Question

（2007天津?qū)氎嬉荒Ｄ�擬）I didn't hear the bell ring; I ________ asleep.

1. A.
   must be
2. B.
   must have been
3. C.
   should be
4. D.
   should have been

Answer 1

B
句意：我那時(shí)沒有聽到鈴響，一定是睡著了。根據(jù)前面didn't hear...的提示，可知本題是對(duì)過去狀態(tài)的推測(cè)，故排除A、C兩項(xiàng)；表肯定推測(cè)B符合題意，而D表示本應(yīng)該做而實(shí)際沒有做的概念。