— Susan, would you like to go hiking with us this afternoon?— I'd love to, but I study for a test.A. may B. have to C. can
________ plastic bags we use, ________ it will be to the environment.
Noise pollution can cause people to become sick. So our government has done________to stop it.
He _______ his head to see the _______ sun.
-These farmers have been to the United States.-Really? When _______ there?
The weather in Beijing is cooler than _______ in Guangzhou.