A computer is so useful a machine ________ we can use everywhere.
| A．that | B．which | C．as | D．what |
If we________ , we can realize the progress we have made in space research.
| A．turn back | B．look back | C．answer back | D．move back |
They arrived at the farmhouse, in front of which _________.
| A．is sitting a boy | B．sat a boy | C．a boy sat | D．a boy is sitting |
—Who are those with the flags?
—A group________itself the League for Peace.
| A．called | B．calls | C．calling | D．is called |
When I was you age, I dared to go out alone at night, ________ you?
| A．dared | B．dare | C．did | D．didn’t |
Everything he ______ away from him before he returned to his home town.
| A．took | B．had been taken |
| C．had had been taken | D．had taken |