power bank

Always carry a power bank when you travel—outlets can be hard to find.出行时随身携带一个移动电源——插座可能很难找。

His power bank ran out halfway through the long train journey, leaving his phone dead for hours.他的移动电源在漫长的火车旅途行到一半时就没电了，导致他的手机没电了好几个小时。