Модальные глаголы и их эквиваленты, выражающие возможность.

	Present	Past	Future
CAN to be able to Выражает реальную возможность, физическую или умственную способность.	CAN am \ is ̶ ̶ able(to) / are I can do it. (I am able to do it).	COULD was \ able(to) / were I could do it (I was able to do it).	— shall \ be able(to) / will I shall be able to do it.
MAY to be allowed (to) Выражает допущение возможности, разрешение совершить действие.	MAY am \ is ̶ ̶ allowed (to) / are You may go home now.	MIGT was \ allowed(to) / were He said I might smoke here. She was allowed to go home.	— shall \ be able(to) / will You will be allowed to swim.

Модальные глаголы и их эквиваленты, выражающие долженствование

	Present	Past	Future	with Perfect Infinitive
MUST Выражает долженствование	MUST I must do it now. You mustn’t do it.	—	—	—
TO HAVE (TO) Выражает вынужденную необходимость	have to has I have to do it now.	had(to) I had to go there. Did you have to go there? We did not have to go there	s hall have (to) will You will have to go there.	—
OUGHT (TO) Выражает моральный долг	ought (to) We ought to help her.	—	—	You ought to have done it yesterday.

SHOULD Выражает необходимость или совет.	should You should not go there.	—	—	You should have helped him.
NEED Выражает необходимость, целесообразность, обычно употребляется с отрицанием.	need You needn̓ t hurry.	—	—	You needn̓ t have done it.
TO BE (TO) Выражает необходимость, предусмотренную планом, договоренностью, расписанием.	a m i s ̶ ̶ to are The train is to arrive at 10.	w as (to) were He was to attend the seminar.	—	They were to have met.