Can you tell the ________ difference between the words “require” and “request”? I sometimes get puzzled by their meanings.

A good diet and some moderate exercise are ____ to good health. 

Owing to over-drinking．his health is ____．

________ and short of breath, Andy and Ruby were the first to reach the top of Mount Tai.

 I felt____after he opened the present. I thought he would have liked it.