Teorija

S + have/has + V3 + O   
  
S - subject: I, we, you, they, he, she, it, Mary, John ...
V3 - the Past Participle of the verb (the verb in the third form): written, eaten, worked, ...
O - object
  
S
have/has 
V3
O
Ihaveeatentwo apples.
Wehaveeatentwo apples.
Youhaveeatentwo apples.
Theyhaveeatentwo apples.
He haseatentwo apples.
Shehaseatentwo apples.
Ithaseatentwo apples.

Short forms:
  
have = 've
I have eaten = I've eaten
 
has = 's
She has eaten = She's eaten