Questions in English language can be formed with or without auxiliaries.
Questions with auxiliaries
To make questions in the simple present and simple past, we normally should use do/does (for simple present) and did (for past simple). These auxiliaries in questions have to be followed by the subject and a verb in base form.
Question + Auxiliary + Subject + Verb base form
- What food do you like? NOT:
What food you like?
- Which DVD did he buy?
Questions without auxiliaries
When a question word (such us Who? What? Which? How many?) is the subject of the verb in the question, we don’t use an auxiliary
- Who (subject) called (verb) you last night on the phone?
- Who drives your car? (of course I have a driver … my driver drives the car)
- What happened after the earthquake?
Note: It is very difficult (and very strange) to stop speaking and start analyzing which word in the subject of the verb or what tense is used in the question. The best way to get use with these rules is to memorize them, then write down as many questions as you can (using simple present and simple past). Once you have the questions on a piece of paper everything you have to do is to correct them and find out where and why you made mistakes. Do this several times and soon you wont make any mistake.
Exercise: Cross out the wrong question.
- What happened/did happen to you?
- What means this word/does this word mean?
- How many people came/did come to this class?
- Which train goes/does go to Dalat?
- What said the teacher/did the teacher say?