Thanks to the measures by the local government the polluted river is becoming clearer a

问题补充：

Thanks to the measures by the local government , the polluted river is becoming clearer and clearer and fish have begun to show up in it.

A. taking

B. taken

C. to take

D. having taken

答案：

A. taking

(答案→)B. taken

C. to take

D. having taken

解析：考查非谓语动词。句意：多亏了被当地政府才去的措施，被污染的河流变得越来越清澈，鱼开始在里面出面。根据语境是措施被当地政府采取，所以用过去分词taken，选B。