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

If I _______ plan to do anything I wanted to, I’d like to go to Tibet and travel through as much of it as possible.

–What do you think the noise was? --It ___________ a cat.

--“Where is Tom?”--“He hasn’t come to school today, I think he ______be ill.”

You have worked for a long time. You ____________ be very tired.