“小电池,你身上怎么有那么多奇怪的符号哇?它们都代表什么意思啊?”一次,外福来问电池。“我身上的‘+’和‘-’这两个符号,你知道是什么意思吗?”电池想先从外福来最熟悉的说起。“这个知道,‘+’代表正极,‘-’代表负极。”外福来老实回答。“如果我身上没标这两个符号,你能分清我的正负极 ”Small battery, how many strange symbols on your body wow? What do they all mean ah?“ ”Once, the blessing to ask the battery. “The two symbols of ’+’ and ’-’ on my body, do you know what it means? ” The battery wants to start with the most familiar to the outsider. “This knows, ’+’ on behalf of the positive, ’-’ on behalf of the negative.” “Fidelity to honestly answer. ”If I did not mark these two symbols, you can distinguish between my positive and negative