— Hi! John, would you like to play football with us? — Oh，I can’t. I ___ my lesson all the morning and still need half an hour.

Although medical science________ control over several dangerous diseases, what worries us is that some of them are returning.

— Did you see a man in black pass by just now? — No, sir. I _______ a newspaper.

She can’t ______ having nothing to do.

 After school we went to the reading-room to do some reading, only to be told that it _____.