Why ________ it get colder when we climb up a mountain? We are getting nearer to the sun!
| A．ought to | B．would |
| C．should | D．must |
The professor could hardly find sufficient grounds _____his arguments in favor of the new theory.
| A．to be based on | B．to base on |
| C．which to base on | D．on which to base |
Many workers were organized to clear away remained of the World Trade Center.
| A．those | B．that | C．what | D．where |
A survey was carried out on the death rate of those who were infected by SARS, ________were surprising.
| A．as results | B．which results |
| C．the results of it | D．the results of which |
In recent years much more emphasis has been put______ developing the students productive skills.
| A．onto | B．in | C．over | D．On |
_____ of water makes Death Valley a desert, but it is by no means devoid.
| A．Lacking | B．Being lack |
| C．Because of lack | D．Lack |