Although China has developed its economy greatly, its per capital GDP is still         one-tenth of the United States.

If a person takes drugs, they will slow down his thinking and ________ turn off his brain. 

He is _____ tearing up what he has written and beginning over again.

It is difficult for children to change their eating habit later in life. _____，parents should encourage healthy eating from an early age.

The charity sale our school organizes every year has taught us much that we would never have________ learned in class.