问题补充:
We should try our best to keep our environment from.
A. polluting
B. polluted
C. being polluted
D. having polluted
答案:
A. polluting
B. polluted
(答案→)C. being polluted
D. having polluted
解析:考查固定搭配和动名词的被动形式;固定搭配:keep sth from doing sth阻止某人做某事;句意:我们应该努力阻止我们的环境被破坏。本句的环境和破坏之间构成被动关系,故使用动名词的被动形式being done。故C正确。