共同属性包括名称，作者，关键字，字数在文档中，也是最后一次的文件打印出来。

Common properties include the name of the author, keywords, the number of words in the document and the last time the document was printed.

youdao

I don't have to go read what it printed out in the screen. This has returned a value that I can use. Because I could do a test to say, is this a return value? If it's not, I'll do something else with it. So the binding is still there, it simply doesn't print it out.

我不想读到屏幕中打印出来的这行字,程序返回过一个我能够使用的值,因为我可以做个小测试，来说明这是否是返回的值，如果不是，我可以做一些其它的事,而这个绑定依然在这儿，没有打印任何东西。

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