Please look over grammar mistakes

Grammar: Could a teacher look over the mistakes of structure and grammar?

The mail got here before the date they said it would get here by.

What determines which videos download at what speed? Some download faster than other ones.

This song isn't your generation. It's normal you don't know it.

What [kind] of font do you want it written?

I wish I know if they are going to win.

Kind Regards