We can’t figure out ______ quite a number of insects and birds are dying out．
| A．that | B．as | C．why | D．when |
Duty is an act or a course of action that people ___ you to take by social customs, law or religion.
| A．persuade |
| B．request |
| C．instruct |
| D．expect |
The rare fish, ___ from the cooking pot, has been returned to the sea.
| A．saved |
| B．saving |
| C．to be saved |
| D．having saved |
The island, ___to the mainland by a bridge, is easy to go to.
| A．joining |
| B．to join |
| C．joined |
| D．having joined |
Tom asked the candy makers if they could make the cholocate easier ___ into small pieces.
| A．break |
| B．breaking |
| C．broken |
| D．to break |
“It’s such a nice place,”Mother said as she sat at the table ___ for customs.
| A．to be reserved |
| B．having reserved |
| C．reserving |
| D．reserved |