英语改错.为什么把it's改为its这两个有什么差别么

英语改错.为什么把it's改为its这两个有什么差别么
I‘ve learned from the internet that you are eagerly to make friends with a chinese to help you study Chinese and it’s culture .I think it will be pleasure to be my friend.I‘m LI Hua ,a senior 3 student in Xiangyang. I am good at both English orchinese ,so I am sure I can be of a great help to you.WE can often write letters,sendE-mail .phone each other or even chatting online ,
in this way you will know more about chinese and my English will get improve as well what do you like it?改错,说明每个错的原因详细点