At times the balance in nature is____, resulting in a number of possibly unforeseen effects.
| A．confused | B．puzzled | C．disturbed | D．troubled |
The lecture，__________ at 7： 00 last night, was followed by an observation of the moon with telescopes.
| A．starting |
| B．being started |
| C．to start |
| D．to be started |
-Can you think of another good idea?
-This is the best way I can imagine __________ the goal.
| A．to achieve |
| B．to achieving |
| C．achieving |
| D．having achieved |
A dinner party was being held in __________ of the great achievements she had made when I called her yesterday.
| A．preparation |
| B．contribution |
| C．celebration |
| D．competition |
All his friends and relatives came to __________ him on his daughter's being admitted to Tsinghua University.
| A．celebrating |
| B．congratulate |
| C．memorize |
| D．respect |
My parents just called to say that they got __________ in a traffic jam.
| A．stick |
| B．stuck |
| C．strike |
| D．stricken |