－Why are there a lot of dead fish in the river?－Because they were by the polluted water.A

问题补充：

－Why are there a lot of dead fish in the river?

－Because they were by the polluted water.

A. caught

B. poisoned

C. burned

D. protected

答案：

A. caught

(答案→)B. poisoned

C. burned

D. protected

解析：考查情景交际。“河里为什么有很多死鱼？”“因为它们是被污水毒死的。”catch“捉到”；poison“毒害”；burn“烧死”；protect“保护”。根据句意可知，选B。