at your convenience和for your convenience有什么区别

at your convenience 和 for your convenience 的区别
1, at your convenience ,在你方便的时候 ,一般用在祈使句句尾,是请求你方便的时候做某事.
2, for your convenience, 为了您的方便 , 一般用在建议你做某事.
例句:
一, at your convenience
1, Please send her the book at your convenience.
这本书，请你得便捎给她。
2, Come by to pick me up at your convenience.
在你方便的时候来接我。
二, for your convenience
1, For your convenience, this application is also included with this article in a download file.
为了方便起见，本文在下载文件中还包含了此应用程序。
2,We also provide assembling and fitting service for your convenience.
为方便阁下，我们亦提供产品装配服务。