They produced two reports, ______ of which contained any useful suggestions.
| A．either | B．all | C．none | D．neither |
The environment will be further polluted unless some measures _____.
| A．are taken | B．will be taken |
| C．are being taken | D．should be taken |
—May I go out tonight?
—Of course you can, _____ you promise to be back before 10 o’clock.
| A．as soon as | B．as well | C．as long as | D．as usual |
The company ran into trouble when it tried to expand too quickly, _____ was that it was short of money.
| A．some of them | B．most of which |
| C．one of them | D．part of which |
The scenery of Jiuzhaigou Valley _____ the tourists from all over the world.
| A．appeals to | B．is appealed | C．appeals | D．is appealed to |
The rule demands that everyone ______ quiet in the school library.
| A．keeps | B．keep | C．will keep | D．should be kept |