Tom ____his homework yesterday, because he was in hospital all day.

---Is Mr Hu in the reading room?---No, he _______be there. He has gone to Tianjin.

 Washington ______ get very hot and sticky in summertime. July and August are usually the warmest months.

— Can I go to the movie, Mum?— Certainly. But you _______ be back by ten o’clock.

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