4.　　　 irrigation 改为irrigate

3.　　　 but 改为and

2.　　　 whom 改为who

1.　　　 brought 改为took

10. 去掉them

　 (十六)

9.√

8．　 去掉to

7．　 before 改为after

6．　 somebody 改为anybody

5．　 the 改为a