如果最外边的引号是单引号，那么不展开变量。
If the single quotation mark is the outermost quote, no variables are expanded.
如果最外边的引号是双引号，那么展开所有变量。
If the double quotation mark is the outermost quote, all variables are expanded.
最外边的Container元素与module . object查询相联系。
The outermost Container element is associated with the module.object query.
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