Modal auxiliaries Vs Primary auxiliaries Primary auxiliaries are be, do, have. They are used to form tenses and to frame short answers. Modal auxiliaries are will, would, may, might, shall, should, can, could, must, dare, need, used, ought. They are used to express moods.
Infinitives in a sentence may be needed to repeat in the next part of the sentence. But without using the verb, noun or adjective, we can simply use the particle ‘to’ to mention the preceding verb. This is called anaphoric ‘to’.
It is very difficult to read for many hours, but I have to
In this sentence, to read is the infinitive and the next part also means the same, to read. But we use only ‘to’ without repeating the verb read.
Thus, the above sentence can be rewriten as :
It is very difficult to read for many hours, but I have to read
She does not love him but she pretends to
I went to the theatre in spite of my parents advice not to
(The anaphoric is used when the same infinitve is to be repeated)
The infinitive forms can have passive voice too.
Active Voice Infinitive
Passive Voice Infinitive
I wanted to meet him.
I wanted him to be met
I don’t know how to handle the problem
I don’t know how the problem is to be handled
I allow him to do the work
I allow the work to be done by him
The perfect infinitive is formed with to + have + past participle. This generally refers to an action that was completed before.
He is expected to have finished his work yesterday itself
To have half done the work by ourselves is better than to have asked the fool to do it
Infinitive and Time reference
An infinitive does not give us a clear idea about the time of action. It mainly depends on the main verb of the sentence or it depends on the special finite to give a time reference.
He is very happy to receive the award (The verb is gives us the present time reference)
He was very happy to receive the award. (The verb was gives us the past time reference)
He will be happy to receive the award. (The verb will be gives us the future time reference)
He wantsto receive the award. (The main verb is in present, and so it gives present time reference)