Subject + Verb + Object
The present simple verb structure in English is the infinitive with exception of the third person singular, which is commonly the Infinitive + S.
We use the Present Simple to:
talk about habitual activities, often with adverbs of frequency
He always plays football on Saturdays
We go to the cinema every Wednesday
talk about facts/permanent situations/truths
They live in England
It rains a lot in Scotland
I am a teacher
talk about/give opinions
I like pizza
We think that is a good idea
Do you like football?
We DO NOT use the Present Simple to talk about the PRESENT
To talk about the PRESENT we use the Present Continuous
I cannot answer the phone, I am cooking dinner
NOT: I cook dinner
NOTE: The facts/permanent situations we talk about using the present simple are true in the present but we are not referring to the present, we are talking about the truth.
In general verbs in the present simple are almost universally regular. There are four verbs that are irregular in the present simple.
These four verbs are fundamental to everyday language use. Only to be is irregular to any standard. The other three verbs simply have an adaptation of the third person S structure.
Please note that to be, to do and to have are auxiliary verbs while to go is a normal verb so in the negative form requires the use of the auxiliary verb
As already stated, most verbs do not change from the infinitive except adding an S for the third person singular. This has the following minor exceptions for spelling:
Present Simple further functions here
Instructions & Directions/Stories & Commentaries/Performative utternaces/Newspaper Headlines
Present Simple to talk about the future here
A timetable/A schedule/A known fact/An arrangement
Present Continuous form and function here
What is happening now
Present Continuous further functions here
Temporary states/Repeated actions/Change/Criticism of consistent behaviour
Present Simple or Present Continuous here
Permananent or Temporary states/Stative or Dynamic verbs