He is reaching his bow and arrow up to the sky.

VOA: special.2009.11.13

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

So if we want to put that in chemical terms, we want to make sure we put these in brackets here, and remember, this is the resonance arrow, it's not a reaction arrow, it's a resonance arrow, so make sure you mark it up correctly like that.

那么如果我们把它类比到化学中来，我们要确保它们都放在括号里，而且要记住，这是一个表示共振态的箭头，而不是表示化学反应的，它是一个表示共振态的箭头，因此请务必像这样正确地标记它。

麻省理工公开课 - 化学原理课程节选

So I'm hitting the up arrow right now.

所以现在我在敲右箭头键。

哈佛公开课 - 计算机科学课程节选