Помоги очень срочно надо!!!! И почему мне нужно объяснять ответ !!! Спасибо заранее

31There are too many cars in the streets of big cities.2 In some African countries kids don`t have enough textbooks.3 There`s much pollution in industrial countries.4 I haven`t 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 o`clock.2 You mustn`t cross the street when the traffic light ghanges.3 My dentist says I shouldn`t 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.