We use "Infinitive" after following phrases.
The Infinitive Without To After Modals
Can - She can speak English Well.
Could - You could phone me yesterday.
May - They may find the solution of their problem.
Might - It might rain today.
Must - You must apologize for what you've done.
Need - I need exercise daily.
Should - Everyone should fight against cancer.
Will - We will go to the cinema tonight.
Would - I would complete my work.
See also Modal Verbs
The Infinitive without to after the following structures
Had better - You had better take decision now.
See also had better
Would rather - I would rather watch football match.
See also would, would rather
Would sooner - We would sooner stay at home than go out.
Why not - Why not play game for change?
Why should we - Why should we agree with them?
The infinitive without to after specific verbs + object
Feel - I feel the fever remain for two or three days more.
Hear - I hear him discuss your matter.
Notice - I notice him take no interest in study these days.
See - They see you work a lot.
Watch - She watches the kids play outside.
Infinitive after let
When "Let" is followed by object.
Let - They let their children decide on their own.
When "Let" is not followed by object.
Let's - Let's watch the movie.
See also causative verbs in English grammar
Infinitive without to after help + object
Help - She helped a blind man cross the road.
See also causative verbs in English grammar
Infinitive After Make + Object
Make - The mother made me bring some grocery.
See also causative verbs in English grammar
English Grammar Gerund
Special Verbs followed by Gerund in passive sense
Gerund after prepositions
Infinitive and Gerund
Infinitive and Gerund - with same meaning
Infinitive and Gerund - with different meaning
Gramm Infinitive