--Do you think Jack will lend us a hand?--He is the last one to help others. He _____lend his hand, though.

What a pity! Considering his ability and experience, he ____ have done better.

 My English-Chinese dictionary isn’t in my schoolbag. Where _________ I have put it?

——Dad, must I finish my homework today?——No, you         . You may do it tomorrow.

--- Listen! David is talking happily with his mother in the next room.　--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.