Sudah & Belum

Sudah = already

Saya sudah menonton The Joy Luck Club - I have already watched The Joy Luck Club.

When put in a verb, 'sudah' gives a transition to make it a past tesnse. eg instead of saying i eat apple, using sudah in the sentence will mean that i ate an apple.

For example: Michael sudah makan? would mean, "Michael, have you eaten?"
James sudah ke universitas? would mean, "Has James already gone to University?"

Belum = not yet
Belum can be used on it's own.... eg, "Michael, sudah makan?" can be replied to with, "Belum!" (not yet!)

Belum can also be used as a question tag.

Anda sudah menonton Sin City, belum? You have already seen Sin City, haven't you?