—_____ the population of the U.S.A. in 2005?—It _____ about 296 million.A. What is; is B. What was; was C.How many was; was
—__________ do I have to change the robot’s batteries? —Every two months.
Mr Chen __________ his mobile phone to the shop because it can’t work at all.
Computers have made a great difference _______ our everyday life.
After half a day’s hard work, we made our classroom look as _______ as new.
_______ provides many hours of air for astronauts in space.