Wind _______ electricity widely in many parts of the world.
| A．is used to produce | B．is used to producing |
| C．used to produce | D．used to producing |
These problems may lead to more serious ones, ifunsolved.
| A．remained | B．keeping | C．left | D．making |
His efforts to raise money for his program were ____ because no one showed any intention to take a cent out of their pockets.
| A．in place | B．in sight | C．in effect | D．in vain. |
Today, people are paying more and more attention to their health, books on keeping healthy extremely hot.
| A．to make | B．making | C．make | D．made |
Green tea, many experts suggest, should be drunk regularly to improve health.
| A．which | B．where | C．when | D．as |
—How was the journey?
—Tiring! I caught the train at the last second but all the seats. I stood all the way.
| A．had been occupied | B．had occupied | C．would occupy | D．would be occupied |