English grammar references - structures of questions, how to form questions: Speakspeak

Structures of questions
If there is an auxiliary (helping) verb (be, have, can, will, etc.) we put it before the subject (he, she, I, etc.)	Is anybody in the office? Have you ever visited London? What time Will they be here?
If there is no auxiliary (helping) verb, we put do, does or did before the subject.	Do you know my older brother? Did he come in time?
We put wh- words (when, where, why, who, how, etc.) at the beginning of the question.	How long have you been waiting for me? Where is their office? Which colour do you like best?
We don't use do, does or did when we use what, which, who or whose as the subject.	What happened to you? Who told you about it?

Questions - common mistakes
Common mistakes	Correct version	Why?
What meant you by saying that?	What did you mean by saying that?	If there is no auxiliary (helping) verb, we put do, does or did before the subject.
You like this film?	Do you like this film?
Where you are going this afternoon?	Where are you going this afternoon?	We put an auxiliary verb before the subject.
You did read the letter?	Did you read the letter?	We put an auxiliary verb before the subject.
Who did give you the information?	Who gave you the information?	We don't use do, does or did when we use what, which, who or whose as the subject.
Does he knows your sister?	Does he know your sister?	When there is an auxiliary verb, the main verb is in the infinitive form.
Where will she studies?	Where will she study?
Can you tell me where can I buy a good camera?	Can you tell me where I can buy a good camera?	Word order in indirect question is the same as in a normal sentence: SUBJECT + VERB +...