optional device是什么意思

optional device
可选的设备
双语对照
例句:
1.
As well as the standard arsenal of technical features-touch-screen,wi-fi,gps,bluetooth and built-in camera-the pre also has an optional charging pad,called the touchstone,which uses electromagnetic induction to charge thedevice wirelessly.
这个手机拥有标准技术的特征触摸屏,无线上网,全球卫星定位系统,蓝牙和内置摄像头pre还有一个可供选择的充电设备,叫做触摸石,就是利用电磁感应原理无线为设备充电.

optional device
双语例句
1. This device frequently appears as an optional subsystem built into GPS receivers.x09
这一仪器经常出现在被引入GPS接受器的可选子系统中.
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2. Air pressure type cooling device a...