If we had taken such effective measures much earlier, the fiver so seriously now.
| A．is not polluted | B．would not be polluted |
| C．had not been polluted | D．would not have been polluted |
The argument is extremely heated ______ there are necessary conditions of existence such as water on the Mars.
| A．that | B．whether | C．if | D．which |
In my home breakfast ______ at 7 o’clock, which has ______ unchanged for 20 years.
| A．ordered; lasted | B．is served; remained |
| C．serves; stayed | D．is ordered; developed |
— It seems that you are familiar with this city.
— I ______ English in a high school here for three years. It' s great to be back!
| A．have taught | B．have been teaching |
| C．had taught | D．taught |
Money is a needful and precious thing, and when ______, a noble thing, but I never want you to think it is the first or only prize to strive for.
| A．well used | B．well using |
| C．to well use | D．being well used |
It was sad to me that they, so poor themselves, ___________ bring me food.
| A．might | B．would | C．could | D．should |