The first- and second-person singular, and the plural present-tense form of a verb. In grammar, the base form of a verb is the simplest form, without a special ending; it is the form listed in the dictionary.
The base form of a verb functions as the present-tense form for all persons and numbers except the third-person singular (which uses the -s form). The base form also functions as the infinitive (with or without to) and as the subjunctive mood for all persons including the third-person singular. In addition, the base form is used for the imperative mood.
Examples and Observations:
- Present Tense
"Men live in a fantasy world. I know this because I am one, and I actually receive my mail there."
(Scott Adams) - Infinitive
"It's always easier to learn something than to use what you've learned."
(Chaim Potok, The Promise) - Subjunctive
"The world is changing, and they are demanding that we find a solution to this conflict."
(Agshin Mehdiyev, Azerbaijan Ministry of Foreign Affairs) - Imperative
"Go to the edge of the cliff and jump off. Build your own wings on the way down."
(Ray Bradbury)

