只因为莫尔不能为自己辨护，米尔便乘机攻击他，这是不公正的。
It was unfair for Mill to attack More just because the latter could not answer( him) back.
他乘机利用她的无知和单纯，这种做法是不光明正大的。
He takes advantage of her ignorance and simplicity; it isn't cricket.
现在，我们应乘机反攻。
We should seize the opportunity to counterattack.
