是否触发CB是在普通攻击计算伤害之前的一个动作
当判定触发CB之后，就把CB的伤害作为这次攻击的伤害了，而且还不能吸血
比如打地狱的小怪,我100%压碎性打击,打出1次1000的攻击伤害,怪物有2000血
开始攻击后就会判断是否触发CB
是CB：计算压碎打击的1000*1/4=400血
不是CB：怪物减少 1000血
不会在同一次攻击中既有CB伤害又有普通攻击伤害
具体的CB定义：
Crushing Blow
This is a chance of reducing a monster's health by X% in a single blow.
-Default: 1/4th
-vs. Players: 1/10th
-vs. Hirelings: 1/10th
-vs. Champions, Uniques, Bosses: 1/8th
-with missile weapons, default: 1/8th
-with missile weapons, vs. Players: 1/20th
-with missile weapons, vs Hirelings: 1/20th
-with missile weapons, vs Champions, Uniques, Bosses: 1/16th
The life removed is also scaled with number of players. So that if a monster has 450% more life due to 8 players (or whatever the value is) the life removed is further reduced by the same amount (450% would equal multiplying by 4.5 so the life removed by Crushing Blow is divided by 4.5).
It is possible to get up to 100% chance for Crushing Blow. Anything above 100% is discarded.
Physical resistance does apply to Crushing Blow damage, but only if the resistance is positive.
Crushing Blow Items stack in most cases.
Since 1.10 Crushing Blow is calculated before your normal damage. So, before doing the damage that you would normally do, there is a chance you will reduce the health of the monster by X% then normal damage apply to the resulting lower life. If you have more than one item with Crushing Blow, the probabilities will be added together. There will be one random check for a Crushing Blow. There is no check for each separate item, so one can not get multiple Crushing Blows in one attack.
来自AS：
http://classic.battle.net/diablo2exp/items/magic.shtml另外，
关于物免，有人说公式是 CB伤害/(1-物免) 估计是正确的
