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。

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That is, if I want to combine two things together in a particular way, I need to make sure that I give it the kind of operand it expects.

也就是，如果我想以一种特定的方式,把两个东西组合到一块，我需要确定,给了运算符它想要的输入。

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