This is copy2.c. At the very beginning I, again, demand say something and then I declare s1 to be a string, aka char *, and I store in s1 the string the user types in.

这是copy2。c，在开头打印一句话，然后声明s1是一个字符串，也叫做char，*，然后把用户输入的字符串存储在s1中。

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You want to use "make sure" to declare that you want something to declare that something needs to be done.

当你声称想要某东西，或表示某事必须做到的时候，可以使用“make sure”句型。

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