下面的清单1包含实现这一目标的基本条件代码。

Listing 1 below contains basic conditional code that could achieve this goal.

youdao

清单 4 中的代码说明了条件的创建。

The code in Listing 4 illustrates creation of the condition.

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根据条件，代码将选择相应类型的对象来处理请求。

Based on the condition, the code selects the appropriate type of object to handle the request.

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So the open curly brace followed by the closed curly brace means everything inside of these curly braces should get executed, but only if that first condition is actually true.

所以左花括号后面跟着,右花括号，这意味着花括号里面所有的代码,都应该是要被执行的，但只有当第一个条件是正确的。

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You can say if this is true, then go and do the following pieces of code or puzzle pieces that are inside this part of the block, else go ahead and do these that are down here.

你可以说如果条件成立，执行下面的代码段,或板块中的拼图，否则跳过去执行这下面的语句。

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As an aside, if you ever just have one line of code that you want to execute, one puzzle piece in Scratch terminology, ; you actually don't need the curly braces; you only need the curly braces if you have two or more lines of code that you want to execute if that condition is true.

此外，如果你只有一行代码,需要执行，在Scratch，术语中叫做,一句代码，你就不需要使用花括号了;,如果那个条件成立，你有两行或更多行的代码时需要执行时,你就需要花括号。

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