A new system allows a combine harvester, say, to send a callover to a tractor-trailer so the driver can unload the grain as and when necessary.
例如，一种新的系统允许联合收割机向牵引拖车发送呼叫，以便司机可以在必要的时候卸载谷物。
2
If your phone has a message system, use that instead and call them back when the movie is over.
如果你的手机能够收有信息系统，你可以使用这种功能，这样，在你看完电影后你就能回复。
3
This means that when your background process actually fires up that UI, the user could be way over in another part of the system, doing something else - such as taking a phone call.