他们派卫兵把守着胡同的入口，这样做使他们容易监视人们的举动。

　　5．They suggest that because people are living longer，they ought to work longer，________governments need to establish a sound social security system.

　　因为人们寿命的延长，他们建议人们也应该延长工作时间，而政府需要建立一套完善的社会保障体系。

　　【答案】　1.it's high time that　2.mean more than 3．whether；or　4.made it easier　5.while

　　Ⅳ.回顾话题

　　尽可能用本单元的词汇和句式完成下列写作任务。

　　李明不仅仅是北京大学的一名学生，他还是一名从事教学的志愿者。他认为该是为贫困地区的孩子们服务的时候了，因此，他决定动身去甘肃，他想利用自己丰富的知识使贫困地区的孩子们上大学成为可能。

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　　【参考范文】

　　Li Ming is more than a student of Beijing University，and he takes up teaching as a volunteer.He thinks it's high time that he served the children in poor areas.Consequently，he decides to set off for Gansu Province，where he wants to make full use of his abundant knowledge to make it possible for children in poor areas to go to college.