When we are in the streets,we can see a lot of public signs.They have different meanings and different colours.It's very important to know their meanings.Because they tell us what to do and what not t...蘇教版的，六年級,你可以去網(wǎng)上查下When we are in the streets, we can see a lot of public signs. They are there to tell us what to do and what not to do. For example, when we are in the zoo, there may be public signs that asks us not to step on the grass or feed the birds. I think it's important to know what the public sign mean. Because they are the rules, and we should obey the rules.這樣行嗎？