Living things are dying out quickly. Let’s ask ____ destroying them in the past years.
| A．what part people have been playing |
| B．people have played in |
| C．what part people have played in |
| D．people have been playing what part |
Every time he tried to start the car, the wheels _____ deeper into the mud.
| A．stayed | B．sank | C．fell | D．dropped |
As the storm drew near, black clouds were _____ over the sky.
| A．smoothing | B．wandering | C．running | D．gathering |
It's no _____ arguing about it, because he will never change his mind.
| A．time | B．while | C．use | D．help |
The city was _____ to me, and I didn't know where to go.
| A．interesting | B．large | C．strange | D．exciting |
The book is not _____ what we paid.
| A．worth | B．valuable | C．cost | D．dear |