Unit 5 Why do you do that?
A. Useful expressions:
1. cover…with sth be covered with sth
I will cover it with some soil. It will be covered with some soil by me.
2. stop v. end, prevent
stop+n./pron./sb(from)doing keep…from doing 阻止……做……
The policeman stopped the car.
We stopped the children from going out.
The rain kept us from going to the park.
3. break the rule(s) 违犯规则（章程）
It is not allowed to break the rules of the school.
类似的用法还有：
obey the law 遵守法律 break the law犯（违）法
break one’s words(promise)违背诺言
work out a rule 制定规则 keep/follow the rule遵守规则
carry out a rule执行规则
4. grow up 成长，长大
What are you going to be when you grow up?
All plants like to grow up towards the sunlight
5. in the past 在过去
In the past , there were no trees left in or around the village.
Cf: in the past/last+ 具体时间
In the last 20 years, China has changed a lot.
B. Sentence patterns:
1. ways of expressing purposes
1)in order to （动词不定式）也可用so as to，或直接用动词不定式作目的状语
注：用 in order to/so as to时， 主句谓语动词与动词不定式中动词的主语是一致的。
People had to walk many miles in order to fetch wood.
He got up early to come to school on time.
In order to/so as to否定式为： in order not to /so as not to
2) so that接从句，也可用 in order that
用so that /in order that时，从句的主语与主句的主语可以是不同的。
He turned up the radio so that everyone might hear the important news.
They are working hard so that they may pass the examination.
2． 被动语态不同时态的表达
一般现在时：am/is/are+done Our classroom is cleaned every day.
现在进行时：am/is/are+being+done The windows are being cleaned by the students.
现在完成时：have/has+been +done Has he been asked?
一般过去时：was/were+done His bike was stolen yesterday.
过去进行时：was/were+being+done His bike was being mended yesterday afternoon.
过去完成时：had +been+done Clothes had been washed before my mother came back.
一般将来时：will/be going to+be+done Where will the big factory be built?
含有情态动词的:can/must/may/should+be+done A few of the trees can be cut each year.