A diary is a book in which you write personal information. You write
in it each day or week. You write about your thoughts and what you did.

The verb TO BE: you can use
the full form or the contracted form (verkorte vorm)

(writing)
I am
he / she / it is

(speaking)
- I'm
- he's / she's / it's  

ik ben
hij / zij / het is