3．沙尘暴经常袭击我的家乡。

　　Sandstorms often strike my hometown．

　　4．沙尘暴使人们遭受很多罪。

　　People suffer a lot from sandstorms.

　　(二)句式升级

　　5．用because 引导原因状语从句连接句1和2

　　Because people in my hometown have been cutting down trees and digging up grass in order to build houses and plant more crops，land gradually becomes desert.

　　6．用非限制性定语从句合并句3和4

　　Sandstorms often strike my hometown，from which people suffer a lot.

　　【参考范文】

　　Dear Editor，

　　I'm a student at a middle school of Shanxi.I'm writing to express my views concerning the environment in my hometown.My hometown used to be a beautiful place.Thick forests and green grass could be seen everywhere.

　　However，nowadays，because people in my hometown have been cutting down trees and digging up grass in order to build houses and plant more crops，land gradually becomes desert.Sandstorms often strike my hometown，from which people suffer a lot.

　　To prevent the process of desertification，I hope all the people take good care of the forests and plant more trees instead of cutting them down.Then our living conditions will soon be improved.

　　I'm looking forward to hearing from you.

Yours，