. Professor Smith and Professor Brown will _____ in giving the class lectures.
| A．exchange | B．alter | C．shift | D．alternate |
ln the struggle of fighting against _______ nature, _______ man created itself.
| A．the; the |
| B．/; / |
| C．a; the |
| D．/; the |
It is suggested that the key _______ the world's environment should be _______ a low carbon economy right now.
| A．to protect; to expand |
| B．to protecting; to expand |
| C．of protecting; expanding |
| D．to protect; expanding |
This washing machine is environmentally _______ because it uses less water and electricity than older models.
| A．friendly |
| B．various |
| C．common |
| D．changeable |
AII the companies had to _______ their expenses in response to the financial crisis.
| A．add up to |
| B．cut back on |
| C．look out for |
| D．refer back to |
In the new term,I'd like you to know the three different _______ to the study of math.
| A．approaches |
| B．means |
| C．methods |
| D．ways |