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   shall 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.	am is ̶ ̶ to are   The train is to arrive at 10.	was (to) were   He was to attend the seminar.	—	They were to have met.

Сводная таблица времён