For some students, the computer serves only _____ a tool that is used to play games.

The parents are _____ their son who has been away from home for days.

Some high officers were punished by law only because they were ______ what didn’t belong to them.

He was hit by a falling tree that night and killed ____________.

_______ his research, man can set foot on the moon now.

_______ the satisfaction of our customers, the products worked very well.

—Quite a lot of students failed in the math exam．
—Exactly．It is ____ their abilities．

We all admired her ______ the way she saved the children from the fire.

It’s not bad manners to play a trick ____ your friend on April Fool’s Day.

You must have been taken ____ by his lies. He is a dishonest man.