系统窗口类由系统注册。

A system class is a window class registered by the system.

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您还没有正式登录或长时间未使用系统，请关闭所有系统窗口重新登陆！

You don't login or haven't used the system for long time, please close all Windows and login again!

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堡垒的保护更容易因为它构造更简单：它没有窗口、几乎没有几道门，没有天窗或通风系统这些入侵者可能利用的东西。

A fortress is easier to protect because it's simpler: it has no windows, few doors, no skylights, or vent systems through which an intruder might sneak.

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