Rewrite the sentences by replacing the underlined expressions with the correct modal verb (couldn't, can, need, needn't, ought to, must). Make the necessary changes. (Перепиши предложения, заменив подчёркнутые выражения подходящим модальным глаголом. Внеси нужные изменения.)
1 Richard has the ability to solve maths problems very quickly. Richard ............
2 It isn't necessary to stay in the exam hall after you have completed the test. You ............
3 I advise you to seek help if you are having problems understanding something. You ............
4 Nia is a very well-behaved child. I doubt that she was nasty to the other children. She ............
5 It is necessary for you to have a computer password. You ............
6 Students are obliged to be on time for class. Students ............
Подбираем модальный глагол по значению; после него идёт инфинитив без to (кроме ought to).
- has the ability to = «умеет, способен» → can: Richard can solve maths problems very quickly.
- It isn't necessary to = «нет необходимости» → needn't (не нужно): You needn't stay in the exam hall…
- I advise you to = «советую» → ought to (следует): You ought to seek help…
- I doubt that she was nasty = «сомневаюсь, что она была грубой» — предположение о прошлом, сильное сомнение → couldn't have + третья форма: She couldn't have been nasty to the other children (она не могла быть грубой).
- It is necessary for you to = «необходимо» → must: You must have a computer password.
- are obliged to = «обязаны» → must: Students must be on time for class.
Остался лишний модальный глагол need — он не нужен в этих предложениях.
