I didn't need to...= it was not necessary for me to... (and / knew this at the time):
In English Infinitive has 16 forms:
In English there are 12 forms of infinitives:
In questions and negative sentences with have to, we normally use do/does/did:
In their primary function, modals closely reflect the meanings often given first in the dictionaries:
Infinitives are always used with to:
Instead of needn't you can use don't/doesn't need to:
Modals can be arranged on a scale from the greatest uncertainty (might) to the greatest certainty (must):
Mustn't and don't have to are completely different:
Nine of the modal auxiliaries (not shall) can be used to express the degree of certainty (uncertainty) a speaker feels about a possibility:
Should is not as strong as must:
To offer to do something, we sometimes use Can/...:
Verbs like can and may are called modal auxiliaries, but we often refer to them simply as modal verbs or modals:
We use modals when we are concerned with our relationship with someone else:
Wheather + infinitive can be used similarly after want to know, wonder:
When the thought concerns a previous action we use the perfect infinitive:
You can use 'have got to' instead of 'have to':
You must do something' means it is necessary that you do it:
You should do something = it is a good thing to do or the right thing to do: