单元知识要点：

　　词汇：

　　No smoking, No littering, No parking, No cycling, No eating and drinking, keep off, Don‘t touch, keep quiet, make noise, walk on the grass, public signs, only four years old, take a walk, ask some questions, stay away from, on the bird’s cage, pick up, ride a bike, take photos, climb the tree, come up, look around, a ten-yuan note

　　句型：

　　What does this/that sign mean?  It means ‘Danger’.

　　You shouldn‘t make noise/park/eat and drink/...

　　You should keep quiet/keep off the grass.

　　Can I ...?     No, you can’t. You shouldn‘t ... now.

　　Can I go in?    No, you can’t. You must stay from the building.

　　语法：

　　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：

　　1、 建议或命令

　　You should go home now.

　　You should brush your teeth every morning.

　　2、 义务或责任

　　You should help your classmates when they are in difficulty.

　　(当你的同学有困难的时候，你应该帮助他们。)