Only when the firefighters put off the fire what great damage it caused.
| A．we had realized | B．had we realized | C．we realize | D．did we realize |
The teacher found ____ difficult to decide ____ he would take with him to attend the conference.
| A．it; whom | B．himself; who | C．this; whom | D．that; who |
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 |
The man who was being followed stopped from time to time ____ he wanted to tie his shoelaces.
| A．as if | B．like | C．what | D．as |
____ he was fired by the company is ____ he didn’t work hard.
| A．What; because | B．Why; because | C．Why; that | D．That; because |
It is well known to us all ____ China sent up a manned spaceship to outer space successfully last year.
| A．that | B．what | C．which | D．when |