Interrupt and prevent on old cards translates to 'negate' (it doesn't work in the reverse, negate is its own ability).
Breakdown of the 'Cannot Be's:
CBP = Cannot be Prevented: Cannot be stopped by a card played before it. That means that prevents or ongoing negates that hit the table before a CBP card do not affect it (regardless of the actual word).
CBI = Cannot be Interrupted: Cannot be stopped by a card played after it. That means that interrupts or negates that hit the table after a CBI card do not affect it (regardless of the actual word).
CBN = Cannot be Negated: Cannot be stopped period. Prevent, interrupt, and negate have no effect on these cards (regardless of the actual word).
Hope this helps.