seriously want to make a sig for this sentence, but... "Google
is your friend!"
anyway, for US unis, need SATs and TOEFL, A levels not too sure
but think they don't care. for UK, since A levels from there,
perfectly fine. but in all cases, check their... wait for it...
university websites!
btw, if you are thinking of studying science &/or
engineering in top unis, make sure you can study REALLY REALLY
hard. cos our sg JC standard for math & science is
terribad.