The document discusses the present simple negative form in English. It explains that to make a sentence negative in the 3rd person singular (he, she, it), we use the auxiliary verb "does" instead of "s" at the end of the infinitive verb. It provides an example of changing the positive sentence "A teacher works in a school" into the negative version "A teacher doesn't work in a restaurant" using the structure of subject + auxiliary verb (not) + verb infinitive.

1. Work places
Unit 4: Lesson 3
Present Simple negative
form

2. Present Simple, the 3rd person
 We use the infinitive of the verb. In the 3rd
person Singular (he, she, it - or a name)
we put an -s at the end of the infinitive.
For example:
 A secretary works in an office.
 A doctor works in a hospital
 A teller works in a bank

3. Present Simple, the 3rd person
(negative)
 We use the auxiliary verb in negative
sentence.
 We change the –s into does.
Structure

4. Structure (negative form)
Subject + auxiliary verb (not) + verb infinitive
A teacher works in a school.
Let’s change into negative!
A teacher doesn’t work in a restaurant.

5. Work places
a doctor in a
a doctor
works