When do I use "who" and when "whom"?

Use who when the person is the subject — the one performing the action: “Who called you?” Use whom when the person is the object: “Whom did you call?” A quick test is to answer the question: if the answer would be he , use who ; if it would be him , use whom . In everyday speech who is accepted for both, but exams still expect whom as the object.

Why is there no "did" in "Who broke the glass?"

Because who is the subject of the sentence, so the normal statement order is already correct and nothing needs to be inverted. Adding an auxiliary — “Who did break the glass?” — is wrong except as heavy emphasis. Compare “What did he break?”, where what is the object and did is required.

What is the difference between "what" and "which"?

Which asks for a choice from a set that is known or limited: “Which of these three shirts do you want?” What asks openly, with no set implied: “What do you want?” When the options are visible or already named, which is the natural word.

Why does "I do not know where he lives" have no auxiliary?

Because the WH clause is embedded inside a statement, so it is no longer a question in its own right. Embedded and reported questions take ordinary statement word order: subject before verb, no do/does/did , and no question mark on the inner clause. This is the same rule that governs narration change.

English · Grammar · SSC & HSC

WH Questions — Rules, Word Order & Exercise

How to form a question with who, what, when, where, why, which, whose and how.

A WH question asks for information rather than a yes or no, and begins with a question word: who, whom, whose, what, which, when, where, why or how. The order is WH word + auxiliary + subject + main verb. The one exception is when the WH word is itself the subject — "Who broke the glass?" — where no auxiliary is added and normal word order stays.

Where it is set: SSC & HSC English 2nd Paper — Grammar

The word order that makes a WH question

A WH question asks for information rather than a yes or a no. The order is question word + auxiliary + subject + main verb, and everything else follows from that.

If the statement has no auxiliary of its own, supply do, does or did to match the tense — and once you have, the main verb returns to its base form, because the tense is now carried by the auxiliary.

Building the question step by step

Statement	Question word	Auxiliary	Question
He lives in Dhaka.	Where	does	Where does he live?
They went yesterday.	When	did	When did they go?
She is reading a book.	What	is	What is she reading?
He has finished the work.	What	has	What has he finished?
They will come tomorrow.	When	will	When will they come?
He can swim well.	How	can	How can he swim?

✗ Where he lives? ✓ Where does he live? — the auxiliary must come before the subject
✗ Where does he lives? ✓ Where does he live? — after does, the base form

The question words and what each asks for

Word	Asks about	Example
who	a person (subject)	Who broke the glass?
whom	a person (object)	Whom did you meet?
whose	possession	Whose book is this?
what	a thing or an action	What do you want?
which	a choice from a known set	Which shirt will you buy?
when	time	When will you come?
where	place	Where do you live?
why	reason	Why are you late?
how	manner or means	How did you come?
how many / how much	countable / uncountable quantity	How much rice do you need?
how long / how often / how far	duration / frequency / distance	How long have you waited?

✓ Which of these books is yours? — which implies a limited set; what does not
✓ How many students are there? / How much water is there? — countable versus uncountable

When the question word is the subject

There is one important exception to the word order. If the WH word is itself the subject of the sentence, no auxiliary is added and the statement order is kept. This is the rule students most often miss.

Test it by answering the question: if the answer would replace the WH word as the subject, no do/does/did is needed.

Statement	Asking about	Question
Rahim broke the glass.	the subject	Who broke the glass?
Rahim broke the glass.	the object	What did Rahim break?
Something happened.	the subject	What happened?
Five students passed.	the subject	How many students passed?
The storm damaged the house.	the subject	What damaged the house?

✗ Who did break the glass? ✓ Who broke the glass? — who is the subject, so no auxiliary
✓ What did he break? — here what is the object, so did is needed

Which word to use for which underlined part

Board questions usually underline part of a sentence and ask you to form a question to which that part is the answer. Choosing the right question word is therefore the first decision, and it follows directly from what the underlined words name.

A person doing the action → who, and remember no auxiliary is added.
A person receiving the action → whom in formal writing, though who is accepted in ordinary use.
A possessive (Rahim’s book) → whose.
A time expression → when; a place → where; a reason (because …) → why.
A manner (by bus, carefully) → how.
A number or an amount → how many or how much.
A thing → what; a choice among named options → which.

✓ He came here by bus. → How did he come here?
✓ Rahim’s book is missing. → Whose book is missing?

Indirect WH questions keep statement order

When a WH question is reported or embedded inside another sentence, it stops being a question and takes ordinary statement word order — no auxiliary inversion, no question mark. This is the same rule that governs narration.

Direct: Where does he live? → Indirect: He asked where I lived.
Embedded: I do not know where he lives. — not where does he live.
After tell me, I wonder, do you know, use statement order: Do you know where he lives?
The question mark belongs to the outer sentence, not the inner clause.

✗ I do not know where does he live. ✓ I do not know where he lives.
✓ Could you tell me when the train leaves? — statement order inside, question mark outside