A compound subject joins two or more nouns, two or more pronouns, or a noun and a pronoun. A compound subject is plural; two or more singular subjects have been combined to make a plural subject. If the subject of a sentence or clause is a compound subject, use the simple form of the verb.

Joon and Hai study English every morning.

He and I sit next to each other.

Ali and I work together.

History and English are both required for all students in my college.