Mastering question words in English requires understanding subtle rules regarding pronouns, determiners, and modifiers. This guide provides more details on using words like what, which, who, whom, how, and why correctly in everyday syntax and sentence structure.
What, Which, and Whose Before a Noun
These question words can function as pronouns without a noun after them:
- What will be the best train?
- There are lots of books here. Which do you want?
- Whose was the idea?
They can also function as determiners, coming directly before a noun:
- What train will you catch? (You will catch a train.)
- Which books do you want? (You want some of the books.)
- Whose idea was it? (It was someone's idea.)
The word Which can also come before one/ones or before an of-phrase:
- Which ones do you want?
- Which of these postcards shall we send to Angela?
The Use of Who, What, and Which
Who always refers to people. Which can refer to people or to something not human. What refers mostly to something not human, but it can refer to people when it comes before a noun.
| Category | Pronoun / Determiner Examples |
|---|---|
| Human | Who is your maths teacher? Which teacher do you have? What idiot wrote this? |
| Non-human | Which supermarket is cheapest? What book are you reading? What do you do in the evenings? |
Note that Who is a pronoun and cannot come before a noun or before an of-phrase.
NOT Who teacher do you have? and NOT Who ofthe teachers do you have?
What vs. Which: Understanding the Difference in Meaning
There is a difference in meaning between what and which:
- What do you do in your spare time?
- What sport do you play?
- Which is the best route?
- Which way do we go now?
We use what when there is an indefinite (and often large) number of possible answers. We use which when there is a definite (and often small) number of possible answers. What relates to the indefinite word a, and which to the definite word the.
- What sport...? (a sport) — (Tennis, or golf, or football, or...)
- Which way...? (one of the ways) — (Right or left?)
The choice of what or which depends on how the speaker sees the number of possible answers. In some contexts either word is possible:
- What newspaper/Which newspaper do you read?
- What parts/Which parts of France have you visited?
- What size/Which size do you take?
Why don't you invite a few friends? ~ What friends? I haven't got any friends.
Who and Whom
When who is the object, we can use whom instead:
- Who/Whom did you invite?
Whom is formal and rather old-fashioned. Who is more common in everyday speech.
When who/whom is the object of a preposition, there are two possible patterns:
- Who were you talking to?
- To whom were you talking?
The pattern with whom is formal.
How to Use "How" in Sentences
How can express means or manner:
- How do you open this bottle? (You open this bottle somehow.)
- How did the children behave? (The children behaved well/badly.)
When it expresses degree, how can come before an adjective or adverb:
- How wide is the river? (20 metres/30 metres wide?)
- How soon can you let me know? (very soon/quite soon?)
We also use how as an adjective or adverb in friendly enquiries about someone's well-being, enjoyment, or progress:
- How are you? ~ Fine, thanks.
- How did you like the party?— Oh, it was great.
- How are you getting on at college? ~ Fine, thanks. I'm enjoying it.
How was the film? / What was the film like?
But What... like? does not refer to well-being:
How's your brother? ~ Oh, he's fine, thanks.
What's your brother like? ~ Well, he's much quieter than I am.
What does your brother look like? ~ He's taller than me, and he's got dark hair.
A Special Pattern with Why
Why (not) can come before a noun phrase or a verb:
- Why the panic? (= What is the reason for the panic?)
- Look at our prices - why pay more? (= Why should you pay more?)
- Why not stay for a while? (= Why don't you stay for a while?)
Modifying a Question Word
We can use an adverb to modify a question word or phrase:
- When exactly are you coming back?
- Just what will tomorrow bring? About how many people live here?
Else has the meaning 'other':
- What else should I do? (= What other things ... ?)
- Who else did you invite? (= What other people ... ?)
We can emphasize the question by using on earth:
- What on earth will tomorrow bring?
We can also use ever:
- What ever/Whatever can the matter be?
- How ever/However did you manage to find us?
- Who ever/Whoever invited that awful man?
This means that the speaker has no idea what the answer is. The emphasis often expresses surprise. The speaker is surprised that someone invited that awful man.
Key Takeaways
- Question words like *what*, *which*, and *whose* can function as pronouns or determiners before a noun.
- *Who* refers strictly to people, while *which* can refer to humans or non-humans, and *what* primarily refers to non-humans.
- Use *what* for an indefinite, large number of choices and *which* for a definite, small number of choices.
- *Whom* is a formal object pronoun, while *who* is more common in everyday speech.
- Modifiers like *else*, *on earth*, and *ever* add emphasis or express surprise to questions.
Quick Practice
Test your understanding of question words by answering these short questions in the comments below:
- Would you use *what* or *which* to ask about a specific book from a small pile of three? Explain why based on the rules.
- Rewrite the sentence "Who did you invite?" using the formal object pronoun.
FAQ
What is the difference between what and which?
We use *what* when there is an indefinite and often large number of possible answers, relating to the word *a*. We use *which* when there is a definite and often small number of possible answers, relating to the word *the*.
Can who be used before a noun?
No, *who* is a pronoun and cannot come before a noun or an of-phrase (e.g., *Who teacher do you have?* is incorrect).
What does "What... like?" ask compared to "How...?"
*What... like?* asks about quality or characteristics (such as personality or appearance), whereas *How...?* can be used to inquire about someone's general well-being.