Uses of the bare infinitive

Some common principal verbs are followed by object + infinitive without to. Common examples of such verbs are: bid, watch, see, let, make, help and hear.

• I bade him come. (NOT I bade him to come.) (NOT I bade him coming.)
• Let him sit down. (NOT Let him to sit down.) (NOT Let him sitting down.)
• I saw him take the money. (NOT I saw him to take the money.) (NOT I saw him took the money.)
• He made me wait. (NOT He made me to wait.)

We both heard him say that he was disappointed. (NOT We both heard him to say that he was disappointed.)

• I watched him jump over the wall. (NOT I watched him to jump over the wall.)

Help can also be used in this way.

• Help him lift that box. (OR Help him to lift that box.)

The infinitive without to is mainly used in an informal style.

• Could you help me find the keys? (Informal) (OR Could you help me to find the keys?)

Note that in passive versions of these sentences, the infinitive is used with to.

• I was made to wait. (NOT I was made wait.)
• He was heard to say that he was disappointed. (NOT He was heard say that he was disappointed.)