Page 498 - Practical English Usage 3ed - Michael Swan, Oxford

questions (2): declarative questions 481
6 Who phoned? I Who did you phone?
When who, which, what or whose is the subject (or part of the subject), do is not normally used. Compare:
- Who phoned? (Who is the subject.)
Who did you phone? (Who is the object.)
- What happened? (What is the subject.) What did she say? (What is the object.)
More examples:
Which costs more - the blue one or the grey one? (NOT Whieh dtJes e8fJt
m6re .. .n
Which type ofbattery lasts longest? (NOT Ylhieh type 6{banef'}' ti6e!1lmt
16nge!1t?)
How many people work in your office? (NOT U6ft1 ''/'!any fH!6ple ti6 ftl6rle . . .n
But do can be used after a subject question word for emphasis, to insist on an answer.
Well, tell us - what did happen when your father found you? So who did marry the Princess in the end?
7 indirect questions: Tell me when you are leaving
In an indirect question, we do not put an auxiliary before the subject, and we do not use a question mark. For details, see 276.
Tell me when you are leaving. (NOT Tell me when are yelt leaving?)
8 prepositions: What are you talking about?
Prepositions often come at the end of wh-questions, separated from their objects. (For details, see 452.)
What are you talking about? (NOT ,Qb6tit whet' are yelt talleiltg?) Who did you buy the ticket from?
What did you clean the floor with?
For negative questions. see 368.
For ellipsis in questions (e.g. Seell fO/III? Coming IOllight?J, see 179.
481 questions (2): declarative questions
In spoken questions, we do not always use 'interrogative' word order.
You're working late tonight?
These 'declarative questions' are often used when the speaker thinks he/she knows or has understood something, but wants to make sure or express surprise. A rising intonation is common.
This is your car? (= I suppose this is your car, isn't it?) That's the boss? I thought he was the cleaner.
We're going to Hull for ollr holidays. - You're going to Hull?
This word order is not normally possible after a question word. Where are you going? (NOT Where yeti are g6illg¥)
page 466