Present Simple explanation

The Present Simple

We use the present simple to tell about someting that is a fact or a habit.

 

The present simple is the base form of the verb:

I work in London.

But with the third person singular (she/he/it), we add an –s:

She works in London.

 

Let's look at these sentences

I play tennis   =   Positive sentence

I don't play tennis   Negative sentence

Do I play tennis?     Question sentence

 

As you can see, it is only the "hoofdwerkwoord" ,or as we say in English, the base form you use in a sentence.