4.

　　5.

　　【答案】　1.at/by；to do；with 　2.of；for；to do；to　3.on/upon/about；no；for；on/upon　4.keep；lose；on 5．behind/back；by/in/round；in on；in at

　　Ⅲ.重点句式

　　1．In fact， (就是你)have the most important role to play in stopping Yellow River erosion.

　　2． (而且)，the success of the programme has greatly improved the lives of the local people.

　　3．Do you (觉得家务活又累又烦)?

　　4． (毫无疑问)it will help us to cure all sorts of illnesses.

　　5． (这是......完美的解决)all your problems.

　　【答案】　1.it is you who　2.What's more　3.find housework tiring and boring　4.There is no doubt that 　5.Here is the perfect solution to

　　Ⅳ.回顾话题

　　用本单元词汇或句式完成下列写作任务

　　五年前我父母失业了，我不得不辍学。于是我决定去找份工作赚钱来养活全家。我把我的想法告诉了父母，他们最终同意了我的想法。我意识到世界上有许多需要帮助的人，尽管我现在不是很富有，但是我将尽我最大的努力捐献尽可能多的钱。

　　【参考范文】

Five years ago，my parents were out of work.I had to drop out of school.Then I made the choice to find a job to earn money to support my whole family.I told my