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.

Note that we use do with I, you and plural subjects. Does is used with singular subjects.

Form: Do/does + subject + present tense form of the verb.

Examples are given below:

The cow eats grass. (Assertive)
Does the cow eat grass? (Interrogative)
Alice sings a song. (Assertive)
Does Alice sing a song? (Interrogative)
She gets up early in the morning. (Assertive)
Does she get up early in the morning? (Interrogative)
I work hard. (Assertive)
Do I work hard? (Interrogative)
She speaks English well. (Assertive)
Does she speak English well? (Interrogative)

Note that if the interrogative sentence is in the negative, we begin it with do not or does not.

Don’t you want to come with us?
Doesn’t she understand what he means?

The question words who, whom, whose, when, why, where, which, how etc., sometimes precede do and does.

Whom do you want to meet?
Why do you want to go there?
Where does he live?
How do you know him?
Who does not love his country?

When the affirmative sentence contains the primary auxiliaries is, am, are, has or have, the interrogative sentence will begin with these words.

She is a doctor. (Affirmative)
Is she a doctor? (Interrogative)
They have a car. (Affirmative)
Have they a car? OR Do they have a car? (Interrogative)
She is very clever. (Affirmative)
Is she very clear? (Interrogative)
She has many friends. (Affirmative)
Has she many friends. OR Does she have many friends? (Interrogative)

When the affirmative sentence contains the auxiliaries can, may, will, shall etc, the interrogative sentence will begin with these words.

She can go.
Can she go?
They will come.
Will they come?
You may take this book.
May I take this book?
I can lift this load?
Can you lift this load?
We must go there.
Must we go there?