But even with advances in power systems and improved lithium-ion batteries, their range on a single charge is limited-and recharging can take hours.
但是即使是先进的动力系统和改善的锂离子电池，还是受到一次性充电电池的限制-他们再充电的时候需要耗费数小时。
When fully dedicated to missile defence, some ships already devote 40% of their power to electrical systems, says Rear-Admiral Philip Cullom, in charge of the navy's fleet readiness.
掌管美国海军舰艇准备工作的Philip Cullom准将说，当完全用作导弹防御时，一些船已经将其40%的能量用于电子系统。
In fact, neighbors now pay her 20 cents to charge their phones, although that business may soon evaporate: 63 families in Kiptusuri have recently installed their own solar power systems.
事实上，邻居们充一次电还给她20美分。不过这桩生意很快就没了：最近克普图速里有60个家庭安装了自家的太阳能发电装置。
应用推荐