6．The scientists are trying to think of ways to __keep__ the water free of pollution.

　　7．From ner confused look，we can know that the question is quite __confusing__.

　　8．She tried hard to __reduce__ her weight by doing exercise every day.

　　Ⅲ.完成句子

　　1．Addicted to the computer games，he can't __focus on the study__ (集中精力学习).

　　2．Just as exercise helps __build up__ (增强)our bodies，reading helps develop our mind and broad our vision into the world.

　　3．The villagers are trying to __keep the river free from__ (使河流免受)pollution.

　　4．This new project will __cause great damage__ (对......造成很大的损害)to the environment because of the pollution.

　　5．It was the driver's carelessness that __led to__ (导致)the traffic accident.

　　6．I often __confuse her with her twin sister__ (把她和她的双胞胎妹妹弄混)because they are so alike.

　　7．The number of employees __has been reduced from 50 to 30__ (已从50减少到30) so far.

　　8．I don't feel I can __comment on their decision__ (对他们的决定作出评论).