He banged his fist on the table.

他用拳头重桌子。

The robber stunned the guard by banging him on the head.

抢劫犯个卫兵的头部使他晕了过去。

The bank had just closed but I banged on the door and—open sesame—they let me in!

行刚刚关门， 不过我敲了敲门─了芝麻开门的咒语，他们居然让我进去了！

She was bang on when she called him an idiot: that’s just what he is!

她叫他白痴，再合适不过了：他就是个白痴！