1.Would you please tell me what the different between Future simple & Future perfect simple is ?
Ex. If I say " I will go home before 6.00 am and " I will have gone home before 6.00 am
A: I will make breakfast at 6am. (the later event in the future)
B: How? You're not even at home.
A: I will have gone home before 6am. (the earlier event in the future).
A: I'm going Paris next year. (the later event in the future)
B: You can't afford to go to Paris.
A: I will have saved enough money by next year. (the earlier event in the future).
You can see that there's an analogy with the past perfect, which you use when you want to refer to two events in the past, one before the other.