Pronoun-verb agreement requires a correct match between a pronoun and a verb based on number (singular or plural).

A singular pronoun requires a verb for a singular subject.

Example: She is expected at noon. (singular subject pronoun)

A plural pronoun requires a verb for a plural subject.

Example: They are expected at noon. (plural subject pronoun)

The pronouns 'what' and 'who' are:

• interrogative pronouns, used to introduce a question;
• relative pronouns, used to introduce a relative clause.

The pronoun 'who' is a subjective form. The corresponding objective form is 'whom'.

Example uses:

What is the name of that restaurant you like? (interrogative pronoun)

I heard what you said. (relative pronoun)

Who is your new science teacher? (interrogative pronoun)

A neighbor who has a garden gave me the tomatoes. (relative pronoun)