People tend to live more happily and longer if they are ________ about life.

He ______ the agreement at the meeting in public and left angrily．

The government should protect the oldvthat

I think our spacecraft(宇宙飞船）is _____slow_____carry large numbers of people to Mars at present.

What should we do for the disabled children in the Children’s Home—You’re supposed to________ a study group to help them.