I will do it和I will do that 有什么不同

I will do it和I will do that 有什么不同 Yes,I will do it什么意思 i will do everything that . I must do it !I can do it !I will do it !什么意思 I shall do sth.I will do sth. 请问这两者有什么不同?谢谢. I ask for only one chance,and I will prove that I will do it i will try my best 和 i will do my best thy和do有什么区别?为什么 i wil I do I will I will do sth 和I'm gonna do sth 有什么区别? ok. i will do it just like what you do .这句话有什么问题么? If I do it ,I will do it ( )(different) I do do feel that I will miss you much.