—I wonder why Susan looks worried today.

  —I’m not sure, but she _____a small accident driving here.

A. could have     B. might have    C. might have had     D. must have had

In those days, the old woman    sit at the gate for hours, waiting for her son to return from the front.

A. could          B. should       C. might    D. would

---I wonder why Mr Green hasn’t showed up at the meeting yet.

 ---I’m not sure, but he _______ in a traffic jam driving here.

 A. could be stuck           B. might stuck

 C. might have been stuck D. must have stuck

“I called you yesterday. A woman answered, but I didn’t recognize her voice.” “Oh, it _____ my aunt Jean.”

A. must be         B. must have been    C. might be         D. can have been

But for your timely help, the boy ______ his life.

         A. must have lost    B. may lose     C. might have lost            D. should lose