His name is 'john' (imiona piszemy duzymi literami). He 'was walking' (Co? Jakie to sa bzdury? wyrzuc ten kiepski translator i zacznij sie uczyc jez. ang) to a good school, he 'has written: 9zly czas) a final exam very well and went to (z gdzie przedimek?) college.
My uncle has lost 'a' (zle slowo tutaj) job.
'Then he set up a small batteries business' (to zdanie nie jest jasne, nie wiem czy to byly 'small batteries' czy jego business byl 'small).
He has 'been' (po co to slowo tutaj? co ono dodaje w zdaniu?) become famous and he opened a big company. His products are sent to many countries all 'owner' (zle slowo) the world.
There have 'been and worse' (popraw tu brakuje cos) days in his life (przecinek przed but) but my uncle is carrying on.