现在完成时和过去时造句.1和2高悬赏

A:There were lots of trees when I visited the hill two years ago.
B:But now the trees have gone.
A:What has happened here?
B:The farmers have cut them down.
A:There were a lot of fish when I visited the lake three years ago.
B:But now the fish has gone.
A:What has happened here?
B:The factory has polluted the lake/ water/ ecosystem.
不懂问我,南无地藏菩萨!