That man over there _____ be Mr Wang . He has gone to Yushu. 

、Tom is a top student in our class , How        it be that he was a failure in the last exam?

 Your teacher ________ very angry at that moment because you talked back to her like that.

--- The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?---____ my students have a try?

—_______ I take the newspaper away, please ?—No, you mustn’t. You _______ only read it here.