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Interrogative determiners: 'which' and 'what'

Level: intermediate

The interrogative determiners are which and what.

which is a specific determiner

Here are three books. Which book do you think is the most interesting?
They have four boys. Which boy is the oldest?
I can’t remember which house Janet lives in.
Which restaurant did you go to?


what is a general determiner

What food do you like?
I don’t know what job she does.

Interrogative determiners 1


Interrogative determiners 2




Hello again drsachin,

The questions themselves don't provide enough context for you to be able to decide accurately between 'what' or 'which'. Please see my response to Imjustaguy below, as well Peter's response to zagrus. Our two comments should help clarify this for you, I think, though please feel to ask us further questions if you have any.

All the best,
The LearnEnglish Team

If i asked question like this;
who do you thinks you are? or whom do you thinks you are?

which one is correct?


Hello Jezira,

In this case, 'who' is the correct form. Also, in general, 'whom' is quite rare in speaking -- most people use 'who' instead of 'whom'.

Please note that the verb is incorrect in your question; the correct form is: 'Who do you think you are?'

All the best,
The LearnEnglish Team

Thanks for acceptance

hello sir i don't speak English , how to try best way spoken English ?

Hello manukumar,

I would recommend you read the How to improve your speaking section on our Frequently asked questions page, where you will find advice on how to use our site for that purpose. Our Facebook page also has lots of useful ideas and links.

Good luck!

All the best,
The LearnEnglish Team

I hear lots of teachers asking students at school, " what grade are you?" Why do not we use " which" instead as there are limited number of grades, i.e. 1 - 12?

Best wishes,

Hi zagrus,

This is an interesting question. Partly it is certainly a case of convention but I think there may be something else here as well.

We generally use 'which' when the choice is limited, as you say. However, the options usually need to be before us. Thus, if the question were asked simply in conversation then we would say 'what' but if the question were asked with a list of possible grades in front of us then we might be more likely to say 'which'. Similar cases would be horoscopes, where we might ask 'which' if we were looking at a list of all twelve on a chart, or regions ('What part of London are you from?' vs 'Which part of London are you from?' if looking at a map of London). However, these are tendencies and conventions rather than firm grammatical rules, so should be treated as guides and rules of thumb.


Best wishes,


The LearnEnglish Team

What's the difference between saying "WHICH restaurant did you go to" and "WHAT university did you go to" if there are a lot of universities and and lot of restaurants? Can't I use the same word, "what" or "which" for both? Thank you.

Hello Imjustaguy,

We use 'which' when we have a specific set or group in mind and 'what' when we don't have a specific set or group in mind. This means that you could use 'what restaurant' or 'what university' in a context when you did not have a specific group in mind, and 'which restaurant' and 'which university' when you do.

For example, in Boston in the USA, there are several famous universities (Harvard, MIT and others). If you're speaking with someone about their university studies in Boston but she hasn't mentioned where she studied, 'which' would be the form you should use to ask the question ('Which university did you go to?'). You could say 'what', but it would sound strange because there is a specific set of universities that has been mentioned.

On the other hand, imagine you've just met someone who is the first person to go to university in her family, but you have no idea where and there is no other specific set of universities that has been mentioned. In this case, 'what' would be the form you should use.

I hope that helps clarify the matter for you.

All the best,
The LearnEnglish Team