And I started looking at how we could build battery back-up systems that could give people five hours, 10 hours, maybe even a full day, or three days' worth of back-up power.
我开始朝如何做备用电池的方向寻找方法 这种备用电池应该能保证5小时，10小时，甚至是一整天， 或是三天的供电。