那位拳击手在最后一轮被一记出其不意的重拳击倒了。

The boxer was ___knocked ___out by a surprise punch in the final round.

他为了保护自己，迅速反应将袭击者打昏了。

He ___knocked the attacker ___out with a quick reflex to protect himself.

头撞到低矮的横梁可能会让你瞬间昏迷。

Hitting your head on a low beam can ___knock you ___out instantly.