Without gravity, we _____ walk on the ground as freely as we do now. 

— Can I pay the bill by check?— Sorry, sir. According to the rules of our hotel, the payment ______ be made in cash.

—Mum, I'm tired.—Well, if you ________ go to bed after midnight every night, what do you expect?

She __________ be here. I saw her come in.

“No student,”the headteacher stressed, “_______ go out of the school after ten o’clock at night without my permission. ”