Our planet is about ______ years old.
John his homework now. He always his homework in the evening.A. is doing; is doingB. does; doesC. is doing; does
— does it take you to go to work on foot? — About half an hour. A. How far B. How long C. How much
Her mother is very strict her. A. on B. in C. with
They arrived Shanghai Sunday afternoon. A. in; in B. at; in C. in; on
You’d better keep the classroom _____. A. cleaning B. cleaned C. clean