Have you seen Shirley since she moved away— Yes. I’ve seen her several times. She comes back tovisit us ______.

I don’t know if it tomorrow. If it ，we won’t go hiking.

ing special about this device—Well, it can ________ between the cancerous and the normal cells under certain conditions.

Do you think it wise for Chinese mothers to try to do everything for their children? —No, that’s　　　they are mistaken.

The reason _____ he was late for school was _____ he had to send his mother to a hospital.