We use the question words who (for people), what/which (for things), when (for time), where (for places), why (for reasons) and how (for more details).
What do I need to know about question words?
I know you know the basics, but questions are quite tricky. Let’s just go over the main rules.
We usually form questions by putting an auxiliary verb, or a modal verb, before the subject.
Does it suit me?
Has Mum called?
Can you get the tea?
Shall I pass you to Oliver?
When the verb 'to be' is the main verb, we don’t use auxiliary verbs.
Is Oliver there?
Was it good?
We can add question words to get more or different information.
Where did you go swimming? > In the swimming pool in town.
Why did you go there? > Because it’s a nice, big pool.
Who did you go swimming with? > With Amy.
What time did you meet Amy? > At 10 o’clock.
Which pool did you go in? > The serious one, without the slides!
How did you get there? > On the bus.
I see that questions sometimes finish with prepositions.
Yes, that’s very common.
Who were you out with?
What have you got that bag for?
What’s all that about?
Where are you calling from?
OK, that all seems straightforward.
Yes, but do you know about subject and object questions?
If who, what or which is the subject of the question, it comes before the verb and we don’t use do as an auxiliary.
Who went out for curry? (subject – who)
What happened? (subject – what)
Which looks better, this or that one? (subject – which)
Object questions follow the structure we looked at before.
Who did you go out for curry with? (subject – you; object – who)
Which restaurant does Oliver like most? (subject – Oliver; object – which)
What did they do after the restaurant? (subject – they; object – what)
I think I understand …
Here’s a little test for you, then. A cat killed a mouse and a dog killed the cat.
1 What killed the mouse?
2 What did the cat kill?
3 What killed the cat?
4 What did the dog kill?
OK, 1 the cat, 2 the mouse, 3 the dog, 4 the cat. Right?
Exactly! You’ve got it.
Any more tricky things about question words?
Well in reported speech or indirect questions, question words come in the middle of sentences. In these types of sentence, the word order does not change. We don’t put the verb to be before the subject or use an auxiliary to form a question, as in a normal question:
I asked her what she was doing at the weekend.
Do you know where the post office is?
Can you tell me how much it costs?
What are you doing at the weekend?
Where is the post office?
How much does it cost?
Hmm, why do you use indirect questions if they are more complicated?
Well, they are more polite, especially if you are talking to a stranger.
OK, I’ll remember to say: 'Do you know where the post office is?'
Good. Can you make that even more polite?
How about: 'Excuse me, could you tell me where the post office is, please?'
Fine! That’ll do. Do you really need a post office?!