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(暗点) 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 . So your shadow is quite short . But in early morning or late afternoon the sun is low in the sky . Its light moves over more of your body . Then your shadow is quite long . Your body keeps a lot of 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 .