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.
Infinitive are non-finite verbs. Infinitive is formed by adding to with a verb that acts as a noun, an adjective, or an adverb in a sentence
When a verb is in its infinitive state, it has no subject or object. It is used to define the action of the verb without tying it to a specific person. It is a verb acting without a subject. The infinitive is the verb in its purest form. An infinitive should be treated as a single word with a single meaning.
List of Infinitive Verbs
Infinitives in Regular Verbs
They were the first to arrive, were not they?
I have to finish this book before march
Do not hesitate to help her
They refuse to talk
Infinitives in Iregular Verbs
To stand up
We have to eat that we may live
I tried to speak English
I do not know how to sing
It seems it is easy to learn English
What is a split infinitive?
Inserting a word or phrase between to and the verb creates a split infinitive
Before the game, the team was told to warm up by running around the field.
What is an infinitive phrase?
A phrase beginning with the infinitive form of a verb that functions as a noun, an adjective, or an adverb in a sentence.
Cena likes to swim and to fish
Cena likes to swim and fish
Other uses of Infinitives
To express purpose or reason
I accepted him to go to the park
I wanted to buy vegetables in the market
Adjective + Infinitive
The concept is easy to understand
English is interesting to read
Noun or Pronoun + infinitive
He asked my brother to stop smoking
My parents asked my friend to read well for the examinations
Too + Adjective + Infinitive
The coffee is too hot to drink
The man is too bulky to enter the room
Infinitive can be used to replace a clause
I know how I can solve the problem
I know how to solve the problem
Generally verbs take to with them to make an infinitive but some verbs become infinitve without to. These are also called bare infinitive or plain infinitive.
I made him go
Let him go
I saw him cross the railway track
The minister helped abolish poverty
The above verbs can take ‘to’ when it is used in the passive voice.