urgent english question

1.Don't get me wrong, What I mean is can you be friends with me?
2.Don't give up, you still have many chance to do this. Cheer you up.
3.I have spent a lot of time on you, don't let me down.
4.Don't mention it, this is my job.
5.Don't take it for granted, it's just because I forgive you so that others forgive you too. Don't do that again!
6.Don't worry about it, i believe that you can do it.
7.Don't you think that it is easy come, easy go? I have spent a lot of money and time on it!
8.To get full marks in exam, easier said than done. So, you should work hard or you can't do that forever.

Perhaps I can help you :)