—Tom, you look tired this morning. What’s wrong?—I was so busy that I didn’t go to bed _____ 12 o’clock last night.
Hurry up! The movie _______ for ten minutes!
--How do you like the twins?--Well, I think the elder sister is _______ but the young sister is _______.
--- There were so many books in the shopping center, I didn't know_______ .
Put on your coat, Jack! It's snowing _______ outside at the moment.
—Is that Tom in the teachers' office?--No, it ________ be him. He's gone to the hospital.