Workers can’t be made ________ for twelve hours a day.
The population of Shanghai is larger than _____ of Shenyang.
Xi’an is a city with many places of interest and _____ tourists come here every year.
—_____ you _____ your homework yet?—Yes, I _____ it ten minutes ago.
—What are you reading about?—It’s about the one-child policy. It says that the policy has_____controlling the population in China.
—Have you cleaned your room_____?—Yes, I’ve_____cleaned it.