By the time I locked the door，I realized I________my keys at home．
| A．had repaired |
| B．had changed |
| C．had forgotten |
| D．had left |
—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
— Where are Maria and Kangkang ? — They aren’t here. They ________ England.
A. have been to B. have been inC. have gone to
—________ the population of the U.S.A. in 2005?
—It ______ about 296 million.
A. What is; isB. What was; wasC. How many was; was
________ of the teachers ______ women in our school.
A. Two third; isB. Two threes; areC. Two thirds; are