You can kind of see where the syntax is going, looks like a loop, but you can kind of put blocks inside of you, and the little arrow suggests that once you get to the bottom just like our socks example, you're gonna do the following again.

从某种程度上你可以看到它的语法构成,像个循环，你也可以把，一些程序块放到循环中，如同短袜的例子，这个小箭头暗示你一旦到达底部,你将会重复接下来的事情。

哈佛公开课 - 计算机科学课程节选

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