I just want to remind you, if I wanted to, for example, type in an expression like that, notice the syntactical form, it's an expression, a number, followed by an operand, followed by another expression.

我想要提醒下大家，如果你想要，例如，输入一个这样的表达式，注意语法形式，这是个表达式，一个数字，后面是一个运算对象，后面是另外一个表达式。

麻省理工公开课 - 计算机科学及编程导论课程节选

Before I type in that expression, I get an error, right?

在我输入表达式之前，出现一个错误，对吧？

麻省理工公开课 - 计算机科学及编程导论课程节选

The answer was, find a mathematical expression depending on the number of inputs.

很不错，答案是，找到一个通过输入数字,计算出来的数字表达式。

麻省理工公开课 - 计算机科学及编程导论课程节选

Which is, and we're going to do some examples of this, initially we just typed in expressions Python into the interpreter; that is,directly into Python And as I suggested last time, the interpreter is actually a program inside of the machine that is basically following the rules we're describing here to deduce the value and print it up.

也就是，我们将会对这一点讲解一些例子，一开始我们只是简单的把表达式输入,到解释器里面去，也就是直接传给,我上次跟大家讲过，解释器实际上是,机器内置的,按照我们描述的规则,来推算出结果值并把值显示出来的一个东西。

麻省理工公开课 - 计算机科学及编程导论课程节选

So. Starting with the shell, I can type in expressions.

好，从sell开始，我可以输入一些表达式。

麻省理工公开课 - 计算机科学及编程导论课程节选