Self study The Infinitive

Use of particle "to"

As a rule, the infinitive is preceded by the particle "to".

The particle "to" is omitted after modal verbs (You can go; You must take it), after the verbs "make, let" (Make him eat; Let her play), after the verb "help" in American English (Help me find my book), and in constructions like "She saw him leave; He heard her sing". The infinitive without the particle "to" is called bare infinitive.

If the verbs "make, help, see, hear" in such constructions are used in the passive voice, the infinitive after them keeps the particle "to": He was made to leave. She was helped to do it. He was seen to enter that building. He was heard to laugh.

If there are two infinitives next to each other connected by "and, or, but, except, than", the second infinitive is often used without "to": I told him to sit down and rest. She didn't know whether to go or stay. There was nothing to do but wait. There is nothing for him to do but watch TV. It's easier to type than write.

But it is often necessary to repeat "to" before the second infinitive for clarity, especially in longer infinitive phrases: I told him to sit down on the sofa and to rest a little. It is easier to type this text than to write it. To buy or not to buy is a hard choice for her.

The particle "to" is often used without the infinitive at the end of the sentence if the infinitive is clearly mentioned earlier in the sentence: He asks me to do this work, but I don't want to. I didn't want to go there, but I had to. He would prefer to sleep till noon if he were allowed to.

(The place of the particle "to" is also described in the part "Split infinitive" at the end of this article.)