Cho dạng đúng của từ

Their (a)   has lasted a lifetime. (FRIEND)

His son's (a)   has not improved much. (BEHAVE)

He draws cartoons for a (a)   magazine. (HUMOR)

For some people, UFOs only exist in films for (a)   . (ENTERTAIN)

The gas from the chemical factory is extremely (a)   . (HARM)

Environmental (a)   is everybody's responsibility. (PROTECT)

Air and water are (a)   in our life. (NECESSARY)

In the future, many buildings will be (a)   by solar energy. (HOT)

My brother can repair electric (a)   very well. (APPLY)

We want to buy (a)   that will save money. (PRODUCT)