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?