4．
阅读短文，下列问题 Light and shadow（影子） are friends.They usually go together. We receive light every day. At the same time, we produce shadow.
Light cannot shine through you. Your body stops it from passing. There is a dark spot on the ground next to you. The light cannot reach the dark spot. This is your shadow.
At noon the sun shines over your head. Your body stops very little light from reaching the ground.
We love light, especially sunlight. Without sunlight, life on earth is impossible. Most of us like to stand in the shadow of a tree in summer. But some people are afraid of their own shadow at night. They do not want to walk in a dark street. They do not want to see the shadow, either. But still light and shadow usually go together.
