I can do和 I can do it 到底哪句正确?

I can do和 I can do it 到底哪句正确? I can do it i can make it和i can do I can't do it ( ) Yes i can do it I can't do it What can i do it I belive i can do it否定句 you can do it so can I I can not do it,nobody,can. what do I can do it I do it because I can do it,I can do it because I