—Excuse me. May I sit here? —I’m afraid you _________. My daughter will come back soon.

-- Can you play the piano?-- ____________________________.

One of our rules is that every student       wear school uniform while at school.

—He must be in the reading-room now. We will find him there. ---No, he _____.Tom said he was ill at home .

--- 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?