balance.

　　A .into B . towards C. about D . on

6. This also keeps the air, soil, water and crops free from chemicals. (Page 14)

　keep...free from/of

① We put our books in bookcase to keep them free from dust.

② He won't be able to keep the truth from his father.

③ You can't keep him from doing that thing. ④ I'm free of that job at last.

⑤ They aim to free the students from too much homework.

[归纳] 1. keep ... from:

　　　2. free from:

　　　3. be free of sb/sth:

[延伸]

1)free from／of意为"无......的""免除......的...""不受......约束的"。如：

　They like living in a village，free from／of crowds and noises．

　他们喜欢住在村子里，远离人群和喧闹。

　She got the ticket free of charge．她免费得到了这张票。

2)keep重点短语归纳：

　keep an eye on照看；密切注视

　keep away from远离；避开

　keep back隐瞒；忍住(眼泪)

　keep company和......在一起

　keep off(使)避开

　keep up with跟上

如：Please keep an eye on our baby． 请照看一下我们的婴儿。

　We kept away from the big dog． 我们远离了那只大狗。

　I'11 keep nothing back from you．

　我将什么也不隐瞒你。

　The pet cat keeps company with him every day．

　那只宠物猫每天和他在一起。

　Keep off the grass．勿踏草坪。

　He does．,hat he can to keep up with his classmates．

　他尽他所能跟上他的同学们。

[活用]

①Something must be done to keep .

A. the boy to make noise B. the boy making noise

C. the noise from making by the boy

D. the boy from making noise

②Eating well and exercising every day cold．

A．keep you back from B．keep you free from