A. We make questions by: moving an auxiliary to the front of the clause or by moving a modal to the front of the clause.
A1. Yes/No questions are questions to which the answer is Yes or No.
B. Wh-words are what, when, where, who, which, why and how. We use clauses with a wh- word.
C. In present simple questions, we use do/ does; In past simple questions, we use did.; but do not use do/ does/ did if who/ what etc. is the subject of the sentence.
C1. Questions ending in prepositions are very common in English. After Who, Which or What we often have a preposition at the end of the sentence.
D. We use negative questions especially to show surprise. (e.g. Didn't you hear the doorbell? I ring it three times.) or when you expect the listener to agree with us. (e.g. Haven't we met somewhere before?' 'Yes, I think we have.')