THE O INFINITIVE

The zero infinitive is used:

1. after most auxiliaries (e.g. must, can, should, may, might)
2. after verbs of perception, (e.g. see, hear, feel) with the pattern verb + object + zero infinitive
3. after the verbs 'make' and 'let', with the pattern make/let + object + zero infinitive
4. after the expression 'had better'
5. after the expression 'would rather' when referring to the speaker's own actions

Examples:

After auxiliaries:

• She can't speak to you.
• He should give her some money.
• Shall I talk to him?
• Would you like a cup of coffee?
• I might stay another night in the hotel.
• They must leave before 10.00 a.m.

After verbs of perception:

• He saw her fall from the cliff.
• We heard them close the door.
• They saw us walk toward the lake.
• She felt the spider crawl up her leg.

After the verbs 'make' and 'let':

• Her parents let her stay out late.
• Let's go to the cinema tonight.
• You made me love you.
• Don't make me study that boring grammar book!

NOTICE that the 'to-infinitive' is used when 'make' is in the passive voice:

• I am made to sweep the floor every day.
• She was made to eat fish even though she hated it.

After 'had better':

• We had better take some warm clothing.
• She had better ask him not to come.
• You'd better not smile at a crocodile!
• We had better reserve a room in the hotel.
• You'd better give me your address.
• They had better work harder on their grammar!

After 'would rather':

Note: this is ONLY when referring to the speaker's own actions - see 'would rather' in section on Unreal past.