a) Read the sentences. Which modals: give permission? express obligation? express lack of necessity? express prohibition? give advice? express possibility? At the sports centre ... 1 You have to/must wear trainers on the indoor tennis courts and football pitches. (it's necessary/it's the rule) 2 You don't have to/needn't be a member of the sports centre to use the swimming pool. (it's not necessary) 3 Members may/can use all of the sports club's facilities. (it's allowed) 4 Children mustn't/can't use the swimming pool without being accompanied by an adult. (it's not allowed) 5 The centre might/may/could be closed to the public on competition days. (it's possible) 6 You should/ought to lock your valuables in a locker to keep them safe. (it's the best thing) b) Find the correct words, giving reasons. 1 You mustn't/needn't dive into the shallow end of a pool. 2 Must/Can we play football in this park? 3 You may/must drink plenty of water to stay healthy. 4 You mustn't/don't have to be a member to use the gym. 5 Can/Must you ask your mum if you have to/can go to the match? 6 It's getting late; I ought to/may go to bed. 7 I'm going to try this new diet; it might/can work. 8 You don't have to/shouldn't miss meals.
В пункте a пояснения в скобках называют значение модальных глаголов. Have to и must выражают обязанность; don't have to и needn't — отсутствие необходимости, а не запрет. May и can дают разрешение; mustn't и can't запрещают. Might, may, could передают возможность; should и ought to — совет. В пункте b:
a) Permission — may, can; obligation — have to, must; lack of necessity — don't have to, needn't; prohibition — mustn't, can't; advice — should, ought to; possibility — might, may, could.
b)
