Since the time humankind started gardening, we _____to make our environment more beautiful.
| A．try | B．have been trying |
| C．are trying | D．will try |
According to Professor Johnson，we don't have to read the book if we don't want to，as it is ______．（ ）
| A． |
worthwhile |
B． |
necessary |
C． |
optional |
D． |
serious |
Dr．Rowan，______ secretary resigned two weeks ago，has had to do all his own typing．（ ）
| A． |
whose |
B． |
of whom |
C． |
of which |
D． |
which |
﹣Shall I order a taxi for Sarah to go to the airport tonight？
﹣______．I'll drive her there．（ ）
| A． |
Have a try |
B． |
Don't mention it |
| C． |
Don't bother |
D． |
Go ahead |
______ us prepare for the exam，the teacher suggested reading through our notes．（ ）
| A． |
To help |
B． |
Helped |
| C． |
Helping |
D． |
Being helped |
﹣Next time you visit Bob，remember to give him a call in advance．
﹣______．I will．（ ）
| A． |
My pleasure |
B． |
No wonder |
| C． |
Good point |
D． |
Never mind |