Such a skilled tennis player knows how to take_____of his opponent’s (对手) chief weakness.

He talks as if he _____ everything in the world.

In the experiment we kept a watchful eye （ ） the developments and recorded every detail.

We’re talking about the piano and the pianist （ ） were in the concert we attended last night.

Three of us will go there, and the rest （ ） to stay here.

The chemical factory was torn down （ ） protecting the environment.

You have to （ ） early in the morning to avoid the rush hour.

It’s high time we _____ strict measures to stop pollution.

It is important that the boy （ ） an adult to take care of him.

We don’t doubt _____ he can do a good job, concerning his experience.

_____ finished his work, he had to stay at home on the weekend.

At the 60th anniversary, the guests sitting in the front are those ______ graduates from the university.