The Infinitive without toafter auxiliaries/modals
| can | He can run very fast. |
| could | As a boy he could run very fast. |
| may | I may fly to Africa this summer. |
| might | I might fly to Africa this summer. |
| must | I must go now. |
| mustn't | You mustn't smoke here. |
| needn't | You needn't go. |
| shall | We shall sing a song. |
| should | We should sing a song. |
| will | She will cook a meal for his birthday. |
| would | She would cook a meal for his birthday. |
after to do
after the following expressions:
| had better | You had better clean up your room. |
| would rather | Susan would rather study for her exam tomorrow. |
| would sooner | I would sooner read a book than watch this film. |
| why not | Why not ask your neighbour for help? |
| why should we | Why should we go by car? |
| why should we not | Why should we not go by car? |
after verbs of perception + object (action has finished):
| feel | She feels the rain fall on her face. |
| hear | I heard Peter sing a song. |
| notice | Mandy noticed the boy climb the tree. |
| see | They saw him climb up the roof. |
| watch | He watched the thieves steal a car. |
after let + object:
| let | Sandy let her child go out alone. |
| Mother let her daughter decide on her own. |
| let's | Let's go for a walk through the park. |
after make + object:
| make | She made Peggy and Samantha clean the room. |
http://www.englisch-hilfen.de/en/grammar/infinitive_without_to.htm
