An ELT Glossary : Base form

The base form of the verb is the verb devoid of any inflections. For example : drink as opposed to drinks, drinking, drank and drunk.

The base form is used ..

1. As the infinitive form: I heard him come in; We decided to go.

2. With imperative force : Stop that!  Be quiet!  Do not disturb.

3. For all persons of the present simple except the third person singular : I/You/We/They live over there.

4. With mandative subjunctive meaning : Is it essential that we be there?