How do they get to school?一They ________ the subway.
We’re programmed to want more food, we won’t have a chance to eat tomorrow.
Have you finished the work yet? — Not yet. I need two more days.
Look! The light is still on. Is Mr Wu working in his office?—No, it _____ be Mr Wu. He has gone to Nanjing for a meeting.
Have you returned the book to the library _______?––Yes, I have _________ returned it.