Summary
In-depth Explanation
The main interrogative pronouns in English are:
what
which
who
whom
whose
These are also called Wh- words or Wh- question words. However, they only act as pronouns when they stand in for the thing or person being questioned or referred to. Let’s go over each one and how to use them.
What
What is used to ask for general information about things or actions, often when there is no set limit on possible answers. For example:
What is your name?
What caused the delay?
Note that when a Wh- word like what comes directly before a noun, it is called an interrogative adjective or determiner, not an interrogative pronoun. For example:
What movie are you watching?
Which
Which is used to ask about people or things when there is a limited set of choices, making it more specific than what. For example:
Here are the options. Which are your favorites?
Which looks better?
Which is yours?
Who
We use who to ask about an unknown person or people, specifically the subject of the sentence (the person performing the action). For example:
Who is coming to the party?
Who called you yesterday?
Who makes these cakes?
Whom
We use whom to ask about people but specifically the object of the sentence (the person receiving the action). In informal speech, whom is usually replaced by who.
Whom did you call last night?
Whom should I speak to about this problem?
Whom is often used after a preposition. For example:
To whom did you send the letter?
With whom are you going to the concert?
Whose
Whose is used to ask about ownership or possession (to ask who something belongs to). For example:
There’s a phone on the table. Whose is it?
Three artists submitted sculptures. Whose will be chosen?
Whose are these?
Subject-Verb Agreement with Interrogative Pronouns
When the interrogative pronoun refers to a plural subject, the verb is usually used in the plural form. For example:
What is your favorite song? → What are your favorite songs?
Here, the verb (is/are) changes to agree with the noun that the question is asking about (song/songs). Here are some more examples:
Who is that? → Who are they?
Whose is this? → Whose are those?
Which was your favorite? → Which were your favorite three?
For whom is this letter? → For whom are these letters?
However, we often use the singular form of the verb with who when it is not certain whether the subject is singular or plural, or to refer to a group of people. For example:
Who is coming to the meeting? (The speaker assumes one or more people will come.)
Who was at the door? (The speaker does not know if it was one or more people.)