I've heard that a verb usually follows the 'infinitive' but how does one define an 'infinitive'?
- Anybody can ask a question
- Anybody can answer
- The best answers are voted up and rise to the top
The infinitive is the basic or root verb form, uninflected.
For example, in "to work" the infinitive is "work":
Other forms are derived from the infinitive:
And so on.
You might see the infinitive is the form of the verb that has most of the following features:
Beware of just saying that the infinitive is the form "without inflection", because some languages have specific endings/inflections that are actually added to the root to specify "infinitive", and infinitives may allow certain modifications e.g. to mark perfective aspect in Slavic languages, to mark reflection/voice in various European languages. They're the form "without inflection" so long as you understand "inflection" in a particular way.
The Cambridge Grammar of the English Language defines an infinitive thus:
Verbs are used various different ways:
The infinitive is another way to use a verb. In English, the easiest ways to identify the infinitive are
The infinitive can't be the main verb of a sentence. It often comes after another verb, like want or likes above. But not always:
The infinitive appears without to in a few places, particularly after the modal auxiliary verbs can/could/may/might/will/would/shall/should/must and after a few other verbs like help.