当表示"灯,电灯"的时候是可数的..
当表示光线的时候是不可数的..
want you to sit right here and don't move,okay?
don't turn on the light.don't turn off the light.
我要你坐在这 不要动 明白吗?
别开灯 也别关灯
So,it's important to get a little bit of a sense of what all these different kinds of lights do.
对所有这些不同种类的光波,有个大致的了解是非常重要的