could: kon, zou kunnen - bij verleden tijd kunnen of een beleefd verzoekCould you lend me some cash?
I couldn't see anything, it was dark.
would: zou, zou willen - vragen wat iemand graag wil, zeggen wat je zou doen
Would you want to live on an island? I wouldn't pet that dog, it looks angry.
should: zou moeten - advies geven
I shouldn't eat so much chocolate, it's bad for me. You should watch The Dream SMP, they're really funny.