To make negatives you simply insert "not" before the verb "to be".

- You are a doctor. ඔබ දොස්තර කෙනෙකි.
- You are not a doctor. ඔබ දොස්තර කෙනෙක් නොවේ.

- They are cats. උන් පූසන් ය.
- They are not cats. උන් පූසන් නොවේ.

Singular

I am not
You are not
He is not
She is not
It is not

Plural
We are not
You are not
They are not

2. Present Simple Questions

To make questions you simply invert the subject and the verb. මෙ සඳහා ක්‍රියාව සහ උක්තය මාරු කෙරේ.

වාක්‍යය - You are a doctor.
ප්‍රශ්නය - Are you a doctor?

They are cats.
Are they cats?

Singular
Am I (a teacher) ?
Are you ...?
Is he ...?
Is she ...?
Is it ...?

Plural

Are we ...?
Are you ...?
Are they ...?

3. Short Answers

- Are you a teacher?
- Yes, I am / No, I am not.

- Is he a student?
- Yes, he is. / No, he is not.

example:
- No, I am not = No, I'm not.