The speed of light 是主语,就是光速
后面是条件状语,用it的话,那么就是指The speed of light了,是想光速怎么会hit呢?是光“hit”,而不是光速.
所以:
The speed of light changes when the light hits the boundaries of different materials.
The speed of light 是主语,就是光速
后面是条件状语,用it的话,那么就是指The speed of light了,是想光速怎么会hit呢?是光“hit”,而不是光速.
所以:
The speed of light changes when the light hits the boundaries of different materials.