无法用存储在变量中的另一个字符串替换字符串

我打了这个:

$folder = 'c:\test'
"c:\test" -replace $folder ""

但是得到这个错误:

At line:1 char:25
+ "c:\test" -replace $folder ""
+                         ~~
Unexpected token '""' in expression or statement.
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : UnexpectedToken

这帮不了我 How to handle backslash character in PowerShell -replace string operations?