В пособии рассматриваются основные моменты английской грамматики: части речи имя существительное, имя прилагательное и наречие; видо-временные формы глагола; модальные глаголы; неличные формы глагола

16. NEEDN’T + Perfect Infinitive

If you say that somebody needn’t have done something, it means that he did
it, but that it was unnecessary: he wasted his time.
You needn’t have woken me up: I don’t have to go to work today.
She needn’t have hurried.

17. NEEDN’T HAVE DONE Compared with DIDN’T HAVE/NEED TO
DO

A. needn’t have done: no obligation but action performed (unnecessarily), i.e.
time wasted:
You needn’t have watered the flowers, for it’s going to rain.
(waste of time)
He needn’t have bought such a large house. His wife would have
been quite happy in a cottage. (waste of money)


B. Didn’t have/need to do: no obligation, and normally no action:
I didn’t need to translate it for him for he understands Dutch.
I didn’t have to cut the grass myself. My brother did it.
(no obligation and no action)

18. Ought and Should for Obligation

A. forms:
The same form can be used for present and future and for the past when
preceded by a verb in a past tense.
ought takes the full infinitive, should is followed by the bare infinitive.
Interrogative: ought I? should I?
Questions or remarks with ought may be answered by should and vice versa.


B. uses, comparing with must and have to
should and ought to are used to express obligation and duty, to give advice,
and in general to say what we think it is right or good for people to do.
You ought to/should go and see ‘Terminator’ - it’s a great film.
You should have seen his face!
Here there is neither the speaker’s authority, as with must, or external
authority, as with have to. It is more the matter of conscience or good sense.
When you use should and ought to, you are saying that the feeling of
obligation is not as strong as when you use must. You also use should/ought
to when you are giving or asking for an opinion about a situation. You often
use ‘I think’, or ‘Do you think’ to start the sentence.
I think that we should be paid more.
Do you think he ought not to go.
What do you think we should do?
In most cases, both should and ought to can be used with more or less the
same meaning. There is, however, a very slight difference. When we use
should, we give our own opinion; ought to has a rather more objective force,
and is used when we are talking about laws, duties and regulations (or when
we want to make our opinion sound as strong as a duty or law).