unit 1 词组
1. four years old 四岁
2. ask ben some questions 问ben 一些问题 （ ask sb. some questions 问某人些问题）  
3. go in 进去     
4. stay away 远离   
5. keep off 远离
6. make noise 发出（喧闹）的声音 
7. talk about 讨论
8. public signs 公共标志  
9. no smoking 禁止吸烟    
10. no littering 禁止乱扔杂物  
11. no parking 禁止停车   
12. do not touch 禁止触摸     
13. danger! 危险  
14. no eating or drinking 禁止吃喝东西
15. keep off the grass 远离草地  
16. be back home from the zoo 从动物园回家
17. be quiet 保持安静 
18. take a walk 散步 
19. a ten-yuan note 一张十元纸币 
20. say to 对……说  
21. pick up 拾起  
22. come up 上来 
23. point to 指向  
24. look around 环顾四周
句型
what does this sign mean?
it means you shouldn’t….
it means you must ....
it means ….
what does it/this/that sign mean?  it means….
you shouldn’t make noise/park/eat and drink/...
you should keep quiet/keep off the grass.
can i …?     no, you can’t. you should… now.
can i go in?    no, you can’t. you must stay from the building.
they mean different things.
you must stay away from the building.
now i know a lot about public signs.

    语法
1.no+v-ing
no parking no eating or drinking  no littering
no smokingno singing    no climbing
no cycling
go+v-ing
go swimminggo fishing      go climbing
go skating   go skiing      go shopping
2.no smoking= shouldn’t smoke
no littering=shouldn’t litter
no parking=shouldn’t park
do not touch=shouldn’t touch it
danger!=should stay away from it
no eating or drinking=shouldn’t eat or drink
keep off the grass=should keep off the grass=shouldn’t walk on the grass
be quiet=should keep quiet=shouldn’t make noise
3.should表示建议，命令，义务，责任的意思，常译作“应当”或“应该”，否定形式
should not (shouldn’t)。例如：
you should go home now.
you should brush your teeth every morning.
 you shouldn’t park your bike here.
4.must 必须，应当 语气比should 来的更强烈。例如：
    you must stay away from the building.
   (注：should , shouldn’t , must 后面都要跟动词原形)
5.ask sb. (人)sth.（事）
give sb.sth.=give sth. to sb.
6.know a lot (副词)   
a lot of public signs (形容词)