下列现象中，能用光的直线传播规律解释的是（ ）
A．海市蜃楼
B．射击时的瞄准要领是“三点一线”
C．雨后天空出现彩虹
D．人不能看见不透明物体的后面
海市蜃楼是光的折射现象，所以A选项不能用光的直线传播解释；
光在同一均匀介质中是沿直线传播的，应用的实例有：日食、月食、射击时的瞄准要领是“三点一线”．所以B选项可以利用光的直线传播规律；
人不能看见不透明物体后面的东西，是因为物体的光沿直线传播，被不透明物体挡住后没有进入我们的眼睛，所以选项D也能用光的直线传播解释；
雨后天空出现彩虹，是由于太阳光照到空气中的小水滴上，被分解为绚丽的七色光，即光的色散，所以选项C不能用光的直线传播解释；
故选BD．
I like best. Last week, I saw a movie called Robot. It tells us a story about the future with robots. It is the year of 2035 and people can see robots everywhere. Robots can help people do a lot of things, like looking the old people or babies, washing, cooking, cleaning or taking dogs for a . Robot does everything people ask them to do. But a policeman Spooner doesn’t like robots. Because he doesn’t think that people can live well robots. One day a scientist kills himself. He leaves a robot. Some time later Spooner finds wrong with the robots in the world. A robots have their own thoughts (思想) and want to control(控制) the people. If the robots succeed, it will be very for people. Susan is another scientist working on robots. Finally, Susan and Spooner decide work together to fight against these robots. At last, they succeed. People control the robots again. I think the movie is very, interesting. you have interest in it, why not go and see it?
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