Closed questions demand a yes/no, true/false or right/wrong answer.

When we want to ask yes/no questions we can use do/does, am/is/are or have/has as question words. We use do or have or am with personal pronouns (I), we use does or has or is with third person singular pronouns (he, she, it) and with singular noun forms. We use do or have or are with other personal pronouns (you, we they) and with plural noun forms.

Yes/no questions with the verb be are created by moving the verb be to the beginning of the sentence. In other words the subject and the verb change their positions in statements and questions.

To Be:

If there is one verb in the statement and the verb is a form of be , simply switch the positions of the subject and verb.

They are students - Are they students?

ToHave:

If there is one verb in the statement and the verb is have, (with or without got to show possession), switch the positions of the subject and verb.

I have a car - Have i a car?

We can also form this style of question with Do…have…? here there is no subject-verb inversion, do is placed before the subject.

Open questions are often called Wh.. questions:-

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

-You use what when you are asking for information about something.

-You usewhento ask about the time that something happened or will happen.

-You use where to ask questions about place or position.

-You use whichwhen you are asking for information about one of a limited number of things.

-You usewho or whom when you are asking about someone's identity.

-You use whose to ask about possession.

-You use why to ask for a reason. 

-You usehow to ask about the way in which something is done.

What is a tag question?

A tag question is a short question added to the end of a positive or negative statement.

How are theyformed?

Normally a positive statement is followed by a negative tag, and a negative statement is followed by a positive tag.

Why do we use them?

Tag questions are used to verify or check information

that we think is true or to check information that we aren't sure is true. Sometimes we just use them for effect.