. — Why does the Lake smell terrible?
—Because large quantities of water______.
| A．has polluted | B．have been polluted |
| C．has been polluted | D．is being polluted |
In order to find _______ better job, he decided to study _________ second foreign language. 
| A．the; a | B．a; a | C．the; the | D．a; the |
—I don’t care what people think.
—Well, you _______
| A．could | B．would | C．should | D．might |
Owen wouldn't eat anythinghe cooked it himself
| A． | until | B． | since | C． | unless | D． | while |
- I wonderyou'll water this kind of flower.
--Every other day.
| A． | how often | B． | how long | C． | how soon | D． | how much |
________ many times, he finally understood it. 
| A．Told | B．Telling | C．Having told | D．Having been told |