Il Presente in inglese, il Simple Present Tense, è ovviamente uno dei tempi più comuni ed ha solo 2 forme: la 3° persona singolare termina con -s, tutte le altre no.

I sing
You sing
He sings
She sings
It sings
We sing
You sing
They sing

Ci sono naturalmente delle eccezioni: i verbi che finiscono per -s, -sh, -ch, -z, -x, -o aggiungono -es alla 3° persona singolare, mentre quelli che finiscono per consonante + -y sostituiscono la -y con un -ies.

He kisses
She wishes
He watches
She mixes
She buzzes
He goes
It flies

Ecco alcuni aforismi per ribadire il concetto di come si forma la 3° persona singolare con questi verbi.

Time flies like an arrow; fruit flies like a banana
Groucho Marx

He who binds to himself a joy
Does the winged life destroy;
But he who kisses the joy as it flies
Lives in eternity's sunrise
William Blake

What a man misses mostly in heaven is company
Mark Twain

Selfishness is not living as one wishes to live, it is asking others to live as one wishes to live.
Oscar Wilde

If one studies too zealously, one easily loses his pants.
Albert Einstein

Forma negativa del simple present

Ecco la forma negativa del simple present tense: si forma con don't + verbo o, nel caso della solita 3° persona singolare, doesn't + verbo.

I don't work
You don't work
He doesn't work
She doesn't work
It doesn't work
We don't work
You don't work
They don't work

A jealous husband doesn’t doubt his wife, but himself.
Honore de Balzac

Forma interrogativa del simple present

La forma interrogativa si forma così do + soggetto + verbo + ? ; per la 3° persona singolare... does + soggetto + verbo + ?

Do I work?
Do you work?
Does he work?
Does she work?
Does it work?
Do we work?
Do you work?
Do they work?

Quando ci sono domande che usano aggettivi e pronomi interrogativi come What, Where, Why, When, Which, Who, si mette l'aggettivo o il pronome interrogativo all'inizio della frase (vedi anche: Question Words, pronomi interrogativi inglesi ):

Why do they work?
What do you study?
Which car does she drive?

Children ask better questions than adults. "May I have a cookie?" "Why is the sky blue?" and "What does a cow say?" are far more likely to elicit a cheerful response than "Where's your manuscript?" Why haven't you called?" and "Who's your lawyer?"
Fran Lebowitz

Forma interrogativa negativa del simple present

Esiste anche la forma interrogativa negativa del simple present:
- Don't (Do not) + soggetto + verbo + ?
- Doesn't (Does not) + soggetto + verbo + ?

Do I not (Don't I) walk?
Do you not (Don't you) walk?
Does he not (Doesn't he) walk?
Does she not (Doesn't she) walk?
Does it not (Doesn't it) walk?
Do we not (Don't we) walk?
Do you not (Don't you) walk?
Do they not (Don't they) walk?