The zero infinitive is used:

a. after most auxiliaries (e.g. must, can, should, may, might)

b. after verbs of perception, (e.g. see, hear, feel) with the pattern verb + object + zero infinitive

c. after the verbs 'make' and 'let', with the pattern make/let + object + zero infinitive

d. after the expression 'had better'

e. after the expression 'would rather'
when referring to the speaker's own actions

 

Examples:

After auxiliaries:

bulletShe can't speak to you.
bulletHe should give her some money.
bulletShall I talk to him?
bulletWould you like a cup of coffee?
bulletI might stay another night in the hotel.
bulletThey must leave before 10.00 a.m.

After verbs of perception: