Nowadays, if you go to outer space, you can check for yourself that if you throw something out, it just goes on forever without your intervention.

现如今,如果你去了外太空,你可以向外抛个物体试试,如果你不打断它,它就会一直运动下去

耶鲁公开课 - 基础物理课程节选

Scratch The syntax actually looks reminiscent to Scratch, where you have a puzzle piece reminiscent of this shape, but you have to say "if" followed by a space, followed by in parenthesis, the Boolean expression that you want to check -- more on those in a moment.

这个语法看起来使人想起，那里有一个这种形状的程序块，但是你必须说明“if“后面跟着一个空格，跟着一个括号，一个你需要核对的布尔表达式,-还有更多的。

哈佛公开课 - 计算机科学课程节选