怎么说呢.主动比被动好.
虽然那句话也对.
但是
这个机构的调查显示,
by括起来不看.
it指代agency,而且是主动.
by后面是状语,删掉不看.
那原句是这样The agency reports that industrial pollutions has been successfully reduced to acceptable levels.就有点儿怪了,不知道是谁的工业污染.
改后是这样,The agency reports that it has succeeded in reducing industrial pollution to acceptable levels.就非常明确了.