Question from English4Today member Mary Gordon in the USA:

Are verb forms in the infinitive the same in meaning and form as base verbs?

Answer

The base form and the infinitive are easy to confuse, Mary.

The base form of the verb is the verb with no tense formation or other grammatical indicator at all e.g., ‘speak‘.

The infinitive is usually written with the ‘to’,e.g., ‘to speak’ (although, there are uses of the infinitive without ‘to’)

Have a look at theses sections on the infinitive in the Online English Grammar.

What is the infinitive?
Using the infinitive
Zero infinitive
Negative infinitive
Infinitive after question words
Other forms of the infinitive
Verbs followed by the infinitive
Verbs followed by a noun + infinitive
Verbs + ‘to’ infinitive, with or without noun
Gerund or infinitive?