Grammar, Punctuation, and Sentences

To avoid confusing your readers, your sentence’s subject (the doer of the action in the sentence) and verb (the action in the sentence) must agree. This means that a singular subject takes a singular verb, and a plural subject takes a plural verb.

Gina highlights her notes. (singular subject and verb)

The girls walk to class. (plural subject and verb)

One of my friends travels every weekend.

Side Note: You won't find the subject within a prepositional phrase. The subject above is the singular “one” not “friends,” so the verb takes the singular form “travels.”