DID THE CHINESE DISCOVER AMERICA?

I DON'T KNOW IF THE CHINESE DISCOVERED AMERICA,  ALL THE TIME, I HAD THOUGHT THAT  COLUMBUS DICOVERED AMERICA, BECAUSE THERE ARE  EVIDENCE THE EXPEDITIONS THERE WAS MADE COLUMBUS (LETTERS AND NAVIGATION ROUTES).
ALL THIS, PROVES THAT COLUMBUS  DICOVERED AMERICA.
AND I THINK, IF THE CHINESE DISCOVERED OUR CONTINENT, WE SHOULD HAVE PHYSICAL TRAITS OF THEM AND EVIDENCE ABOUT THEIR DICOVERED.
AND MY OPINION, ONLY HAVE A HISTORY ABOUT THIS IN OUR BOOK.