The basic rule for asking questions in English is straightforward: Invert the order of the subject and the first auxiliary verb.
- It is snowing. = Is it snowing?
- He can speak German. = Can he speak German?
- They have lived here a long time. = Have they lived here a long time?
- She will arrive at ten o'clock. = Will she arrive at ten o'clock?
- He was driving fast. = Was he driving fast?
- You have been smoking. = Have you been smoking?
If there is no auxiliary, use part of the verb 'to do'.
- You speak fluent French. = Do you speak fluent French?
- She lives in Brussels. = Does she live in Brussels?
- They lived in Manchester. = Did they live in Manchester?
- He had an accident. = Did he have an accident?
Most questions with question words are made in the same way:
- How often does she use it?
- Why don't you come?
- Where do you work?
- How many did you buy?
- What time did you go?
- Which one do you like?
- Whose car were you driving?
Note who, what and which can be the subject. Compare:
- Who is coming to lunch? (who is the subject of the verb)
- Who do you want to invite to lunch? (you is the subject of the verb)
- What happened? (what is the subject of the verb)
- What did you do? (you is the subject of the verb)
Note the position of the prepositions in these questions:
- Who did you speak to?
- What are you looking at?
- Where does he come from?