Помоги очень срочно надо!!!! И почему мне необходимо изъяснять ответ !!!

3
1There are too many cars in the streets of big cities.
2 In some African countries kids dont have enough textbooks.
3 Theres much pollution in industrial countries.
4 I havent got much homework to do this weekend.
5 Have you got enough money to buy the book?

4 
1 Everybody must be here by 8 oclock.
2 You mustnt cross the street when the traffic light ghanges.
3 My dentist says I shouldnt eat too many sweets.
4 You look tired, I think you should have a rest.
5 All exits must be kept clear in case of fire.