The math problem is so hard. I really don’t know .
| A．how to do it | B．how to do | C．what to do it | D．where to do it |
Mr. Smith didn’t tell us ______.
A. where he livesB. where he livedC. where did he live
—How many people did you see in the meeting room?
— ______.
A. Nothing B. No one C. None
— Your bike is very beautiful. How long ____you _____it? — Just two weeks.
A. have; bought B. did; buyC. have; had
—Look! What a nice classroom! — Yes, it ________ every day.
A. is cleaningB. has cleaned C. is cleaned
—It smells terrible. What has happened here?
—Look, there is a chemical factory ____waste water___ the river.
A. pour; intoB. pouring; intoC. poured; to