Mary, where’s Simon? I haven’t seen him for days.–He __________ Japan. This may be the third time he _________ there.

Is Mr. Green in the office?—No, he ________ be in the office. Look, the light in the office is off.

I feel tired and sleepy.— Why not stop ______ yourself?

Mr. Tiger is always cheerful, and he is always friendly to his students.

My grandmother a lot of changes in Tianjin since she came here.