Do or does
The forms “do” and “does” of the verb “to do” are in present tense form. The key to understanding whether to use “do” or does” is to determine whether the noun in the sentence is singular (and the person neither "I" nor "you") or plural.
A singular noun refers to only one person, one place or one thing, and requires a singular verb. The verb “does” indicates the action performed by a singular noun and is, therefore, a singular verb. Examples of singular nouns are, He, She, It. These singular nouns require the use of the singular verb “does”.
A plural noun refers to more than one person, place or thing, and requires a plural verb. The verb “do” indicates the action performed by a plural noun and is, therefore, a plural verb. Examples of plural nouns are, They, We, You. These plural nouns require the use of the plural verb “do”.