________ your letter, I would have set off two days ago.
| A．If I could have received |
| B．Should I receive |
| C．If I received |
| D．Had I received |
3. Jane was permitted to begin her work after .
| A．the chimp family woke up | B．she lived in the forest |
| C．her mother came to support her | D．she arrived at Gombe |
2. Why did Jane go to Africa to study chimps in the wild? Because she wanted .
| A．to work with them in their own environment | |
| B．to prove the way people think about chimps was wrong | |
| C．to discover what chimps eat | D．to observe a chimp family |
II. Choose the correct answers after reading the passage.
1.What did the group do first in the morning? They .
| A．went into the forest slowly | B．left the chimp family sleeping in a tree |
| C．observed the family of chimps wake up | D．helped people understand the behaviour the chimps |
20. The American Civil War lasted four years the North won in the end.
| A．after | B．before | C．when | D．then |
19. into use in April. 2000, the hotline was meant for residents reporting water and heating supply breakdowns
| A．Put | B．Putting | C．Having put | D．Being put |