Once harm ______ to the environment, it takes years to have the system recovered.
| A．does | B．is done | C．will be done | D．be done |
For those who don’t have to safe water, life is a constant struggle.
| A．approach | B．access | C．way | D．passage |
All over the world the mobile phone has leaped from being an impossible luxury in the early 1980s to most people would now call a necessity.
| A．which | B．that | C．what | D．when |
The Washington-Beijing relationship was now about more than trade. It also covered climate and other matters of international .
| A．standard | B．concern | C．expectation | D．chance |
However, at times this balance in nature is disturbed, a number of possibly unforeseen effects.
| A．lying in | B．calling in | C．resulting in | D．taking in |
Why don’t you bring to his attention that you are too busy to do it?
| A．which | B．it | C．what | D．that |