School's(?) opening day

Today is my school's open day. (Today, my school opens.) I went to school by (on) a bike(?) with my little sister. I'm so glad because this is my first time going to college with my little sister, actually she is working in Shenzhen. I love her and I just hope she can live a better life. I'll help her by do my best(?). I will do by best at trying to help her. 
I wanna (want to) speak English very well, so I'll work hard. And I love Japanese, I wanna (want to) go to Japan, maybe as an exchange student is(?) best? Maybe going (to Japan) as an exchange student is best? I believe I can do it. If you dream it, just do it.

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您很好！^^'