During conversation it is common to make a statement and then ask for confirmation. For example, in the sentence ‘It is very hot, isn’t it?’ we make a statement and then ask for confirmation. Here the later part (isn’t it?) is called a question tag.

In question tags we use the following patterns:

Verbs in the simple present and simple past tense do not consist of auxiliary verbs. Their negatives are made by the addition of the anomalous finites do not, does not or did not before the main verb.

The present continuous tense indicates the continuity of an action which is going on at the present moment.

Form: Subject + is/are/am + -ing form of the verb.

I am doing sums.
We are looking at the black-board.
They were playing with the toys.
She is writing a letter to her friend.
They are waiting for us?
They are going to the market.

Simple present

The simple present tense has the following structure:

Subject + present tense forms of the verb (bare infinitive)

The sun rises in the east.
The cow eats grass.

In order to change an assertive sentence in the simple present tense into an interrogative sentence, we use do or does as the first word followed by the subject, verb and the object.