Oh my gosh, my piano exam is in 4 days!!!?

I'm having problems with Lv 8 Technical- Scales, Chords, Arpeggios. For Four Note Tonic Chords, I can't seem to memorize or find out the Cadence, I find it really hard and because of the sharps and flats, I can't find the Cadence. Any tips? Why is it so hard for me to do like B major harmonic? I always have to try the first 4, get the right notes and then play, but at my test, I can't do that. Any tips on that too? I also have a problem on Four Star, I can't remember the melody playback pieces. I can't ever get the first note right. Someone please help me.