Wh-words are what, when, where, who, which, why and how.

We use clauses with a wh- word:

  • In wh-questions (see Questions and Negatives):

What are you doing?
Who ate all the pies?
Why did you do that?

  • after verbs of thinking:

know - understand - suppose - remember - forget - wonder

I know where you live.
She couldn’t remember who he was.
John wondered what was going to happen next.

NOTE: We also use clauses with if

I wonder if we’ll see Peter.
She couldn’t remember if she had posted the letter.

  •  after verbs of saying:

ask - say - admit - argue - reply - agree - mention - explain - suggest

I asked what she wanted.
He tried to explain how the accident had happened.
She wouldn’t admit what she had done.
Did he say when he would come?

tell and some other verbs of saying must always have a direct object (see clauses, sentences and phrases):

tell - remind

We tried to tell them what they should do.
She reminded me where I had left the car.

  • after some verbs of thinking and saying we use wh-words and the to-infinitive:

We didn’t know what to do.
We will ask when to set off.
Nobody told me what to do.
Can anyone suggest where to go for lunch?

NOTE: We use the to-infinitive:

-- When the subject of the to-infinitive is the same as the subject of the main verb:

He didn’t know what to do >>> He didn’t know what he should do
We will ask when to set off >>> We will ask when we should set off

-- When the subject of the to-infinitive is the same as the person spoken to:

Nobody told me what to do. >>> Nobody told me what I should do.
Can anyone suggest where to go for lunch? >>> Can anyone suggest [to us] where we should go for lunch.

  • after some nouns to say more about the noun:

Is there any reason why I should stay?.
Do you remember the day when we went to Edinburgh.
That was the town where I grew up.

We often use a wh-clause after is:

I missed my bus. That’s why I was late.
This is where I live.
That’s what I thought.
Paris – that’s where we are going for our holidays.





One of the last point says using wh-clause after some nouns to give information about the noun. I was wondering whether "that" and "which" can do the same job here?

For example, are there any differences in below sentences?
1) This is the table where the legs are yellow
2) This is the table that the legs are yellow
3) This is the table which the legs are yellow

What I want to know is whether the "where, that and which" are doing the same functions as giving more information to the noun ie table here? If they are the same, are there any differences in meaning between the sentences?


Hello Hugo,

Yes, you could use 'that' or 'which' in a similar sentence, e.g. 'Is that the bus that goes to Manchester?'. You could also 'which' instead of 'that' and there'd be no difference in meaning.

By the way, the three sentences you wrote are not correct – 'that' needs to be followed by a verb and complement in 2 and 3. I'd recommend something like 'This is the table that has yellow legs' as an alternative.

All the best,
The LearnEnglish Team

Hi Kirk,

Followed what you say, is verb the only form that it can take after "where, that and which"?

I read your relative pronoun passage. One of your example used that as in 'the house that Jack built'. Isn't Jack in this sentences a noun?


Hi Huong,

The relative clause tells us more about the noun which precedes it and it can be followed by just a verb (in which case the relative pronoun is the subject of the verb) or a noun + verb (in which case the relative pronoun is the object of the verb). For example:

This is the house that scares me. [the subject of 'scares' here is 'that', which refers to 'the house']

This is the house that my friend built. [the subject of 'built' is 'my friend', and the object is 'that', which refers to 'the house']


When Kirk said that the relative pronoun needed to be followed by a verb he was talking about the examples you gave, not all examples. The problem with your sentences is that the relative clauses do not relate to the relative pronoun: they are neither the subject nor the object of the verb.

For more information on relative clauses please take a look at this page.


Best wishes,


The LearnEnglish Team

Hello Peter,

Thanks for your examples and explanations. Now I know where my problem is. I'll keep improving.


Hello Peter,

If I use 'of which' in the sentence as ' this is the table of which the legs are yellow', would it be correct?


Hello Hugong,

No, you need to use 'whose' in this sentence and cannot replace it with 'of which'.


Best wishes,


The LearnEnglish Team

Hello Peter,

Thank you. But just wondering isn't 'whose' only used to refer to people?


Hello Hugong,

We use 'who' only for people but 'whose' is used for both people and things.


Best wishes,


The LearnEnglish Team

Hello Peter,

I got it. Thank you very much.