She looks sad. Do you know why?—Her son went to study in Canada. I think she _________ him.

Why are you standing, Alice?—I can’t see the blackboard clearly. Two tall boys are sitting _______ me.[ ]

Is the computer ? We don’t have to buy it .

It _________ rain this afternoon, but I am not sure.

The professor has given us _______________ advice on how to improve our memory.