Having lived in China for 8 years, Helen has a good ____________ of both English and Chinese.
to his teaching work, she has no time to take care of her own child.
The sand in the river is increasing these years. We must to protectthe environment.
The idea puzzled me so much that I stopped for a few seconds to try to .
Her joke went too far. It was more than I could .
The employee to impress the company with his cleverness and promptness.