Smoking is bad for your health.— Yes, I know. But I simply can’t ____________ .

There is ________“s” and ________“f”in the word “useful” .

Don’t stay in studying all day. _______.—It sounds quite reasonable. What about play basketball?

The level of the river ___ 20 centimeters over the security line and ____must be taken to control the flood.

Thousands of people have been moving to Shenzhen since 1992, its population to over 10,000,000.