他取出雪茄，敲掉烟灰。

He removed the cigar, knocking off the ash.

youdao

一次敲掉所有销钉的人被称为地板匠。

The person knocking down all the pins at once is known as a floorer.

youdao

你把最后一罐从我手里敲掉还记得吗？

You knocked the last one out of my hand, remember?

youdao

So in a moment you're going to go ahead and hit the spacebar and then as things fall from the screen when they line up with the left arrow, hit the left arrow with a different arrow, hit that arrow and see how good a score you can get.

一会儿你走到前面，敲一下空格键,当屏幕上面的东西从左边往下掉的时候,你就敲一下键盘上的左键,是哪个方向，敲对应的方向键就可以了,我们来看看你能得多少分。

哈佛公开课 - 计算机科学课程节选