Flight controllers at Nasa working out how to get the crippled Apollo 13 back to Earth.
Finally, really small actuators made using traditional electric motors tend to get too hot for their own good at such scales – another headache.
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“脚要踩在大地上。我们干任何事情都有内在规律。”
Archive: ITV news, BBC
Speech recognition helps with pronunciation, while offline downloads let you practice mid-flight or during a commute. Progress syncs across phone and desktop, so learning doesn’t depend on one device. Instead of cramming a phrasebook before departure, you build familiarity over time — enough to understand replies, not just deliver rehearsed lines.