问题补充:
The river is said in a fire during the past 10 years.
A. to have polluted
B. it has been polluted
C. to pollute
D. to have been polluted
答案:
A. to have polluted
B. it has been polluted
C. to pollute
(答案→)D. to have been polluted
解析:考查句型:sb/sth is said to do/to have done,据相信某人/某物…,如果是将要做,用不定式一般式to do如果是已经做了,用不定式的完成式,句意:据说这条河在过去的里已经被污染了,用不定式完成式的被动,选D。