_____ private cars are bringing us convenience, they may also cause more traffic accidents and pollution.

________ the boss has arrived, let’s begin our discussion right away.

— Will you go out to play for a while, Kate? —Not         I finish all of my homework.

____ the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.

The children ran away from the orchard(果园)________ they saw the guard.