打蛇打七寸

说明我们打蛇 没有打在七寸上

(这些人还敢在底下搞动作) ── Previous context

“That means we haven't hit them where it hurts.”

打蛇要打七寸

(你外甥女都知道) ── Previous context

“Strike a snake at its vital spot.”

那打蛇 要打七寸

(他自己说他伤了腿) ── Previous context

“Of course, we should go for the fatal spot.”