I was hoping someone from the USA could give me a hand with this.
Firstly, I have to say that although I was born in the USA, we immigrated to the UK when I was 5. I would like to attend university in the USA - do you guys think you could answer a few questions about the SATs and university?

Why do you take the SAT at the end of your junior year or at the *start* of your senior year? Why not at the end of the senior year? I mean, what do you do for the rest of the year? Is there any big, finishing exam at the end of grade 12? In the UK we just have a final exam at the end of year 12 - but I'm guessing it's different for you.

and

In the USA, when do you start submitting applications for college - while you are still in high school, or when you've finished?

and

How many applications do you usually submit? Do you usually just aim for one college, or do you send in an application to dozens and hope one accepts you?

and (sorry)

What's the deal with the SAT II -- what time of year do you take it? I know to apply as an international student, I have to take three SAT IIs in any subject - is that the same for American students?

Thank you so much if you can help me out here.