The research is so designed that once _____ nothing can be done to change it.
| A．begins | B．having begun | C．beginning | D．begun |
_______ in the Moluyuan on a March afternoon, he could feel the warmth of spring.
| A．To walk. | B．Walking |
| C．Walked | D．Having walked |
You should correct all the mistakes as soon as possible before the book _____.
| A．goes out | B．puts out | C．sets out | D．comes out |
How can they learn anything _____ they spend all their spare time watching television?
| A．for | B．when | C．while | D．because |
We congratulated Jerry ____ the championship.
| A．on winning | B．winning |
| C．to win | D．about winning |
It took my father half an hour to finish ____ my bike.
| A．repairing | B．repair | C．to repair | D．repaired |