There are eight wh-questions, which, what, who, whom, whose, when, where and why and to this list we usually add how as they are all used to elicit particular kinds of information.

Who, what, which and whose can all be used to elicit information about the subject or object of the sentence.

Whom can only be used to elicit information about the object of the sentence. Although using whom would be grammatically correct, we normally use who instead because it doesn't sound so formal.

When which, what, who or whose refers to the subject, the question word comes before the verb without the use of the auxiliary do.

Note that who always refers to people and that before nouns which and what can refer to things or people:

• Who won the race?
  Barry. Barry won the race.

• Which train arrived first ?the 7.15 from Reading or the 7.30 from Oxford?
  The 7.15 from Reading arrived first.

• Which trainee received the best-student award?
  The one from India got the first prize.

When the question word is the object of the sentence, we have to use the auxiliary do:

• So, if Barry won the race, who(m) did he have to beat?
  He had to beat Simon and Pierre.

• Which train did Susan catch?
  She caught the 7.15 from Reading.

which or what?

When there are only two or three possibilities to choose from, which is normally preferred.

When there are an unlimited number of choices, what is used.

Compare the following:

• Which biscuits do you want me to buy ?milk chocolate or plain chocolate?
  I’d like the milk chocolate ones, please.

• What kind of work do you do?
  I work as a lawyer for a firm in the city.

whose

Whose indicates possession, and like which and what, can be used with or without a noun as a question word.

Compare the following:

• Whose coat is this?
  It's Joan's.

• Whose is that red car across the road?
  It's the electrician's.

• What precautions did you take?
  I made sure I was wearing lots of warm clothes.

• What did you do then?
  I simply set off through the snow.

when, where, why and how

These question words elicit an adverbial expression and ask for information about time (when), place (where), reason (why) and method or way in which something is done (how).

Compare the following:

• When will you next be in London?
  The week after next.

• When are you getting married?
  I'm not sure, next summer or autumn, perhaps.

• Where are you getting married?
  In an old church near my village. It's such a romantic place.

• Where does your fiancée come from?
  She's from Ecuador.

• Why didn't you get married earlier?
  We've both been too busy, I guess.

• How was your holiday?
  Oh, it was great. Just what we needed.

• How do you like your coffee?
  With just a dash of milk and two sugars.

• How about some cake to go with it?
  OK, why not?

If you want to practise using some of these words look at our board in the You, Me and Us part of our website.