Verbs that are used to make statements and ask questions are said to be in the indicative mood. The subjunctive mood is used in English to express wishes, commands, suggestions and possibilities.
A verb that expresses a command or request is said to be an imperative, or to be in the imperative mood. Moods in grammar are different forms of a verb that express, for example, whether the action of the verb is a statement or a command, or a fact, a wish or a possibility.
The form of a verb that is used for the first and second person singular and the first, second and third person plural of the simple present tense is the base form of the verb, the simplest form of the verb with nothing added on to it. The simple past tense of a regular verb is generally formed by adding -ed to the stem. The present participles of regular verbs are usually formed by adding -ing to the base form. The past participles of regular verbs are always the same as the simple past tense forms.
The tense of a verb shows whether the action of the verb happens in the past, the present or the future, whether it is a single action or a repeated action, whether the action is completed or unfinished, and so on.
When making a verb agree with its subject, what is important is whether the subject is grammatically singular or plural, not how many people or things the subject refers to. Sometimes it is not the immediate subject, or what seems to be the subject, of the verb that determines whether the verb must be singular or plural, but some other word or phrase in the sentence.
For almost all verbs, the first and second person singular and the first, second and third person plural of the present tense are represented by a verb that is identical to the base form of the verb, while the third person singular verb ends in -s.
Verbs may have different forms depending on whether their subjects are in the first person, the second person, or the third person, and whether they are singular or plural. Verbs may also change their form depending on whether they are referring to the past, the present, or the future.