Have you had this experience? You are watching a movie. A man is shooting on the screen. The picture is so real that you think he is shooting at you. Or a car is speeding on the screen and at one point you are afraid that it will hit you. Three-dimensional(3D)movies use special technology to make pictures seem more real and exciting than two-dimensional ones. The popular movie Avatar uses 3D technology. So far we can only see 3D movies in the cinema with a special screen and projector .But soon, we will be able to watch them in our living rooms. Last month, Woods Company told reporters that it plans to bring 3D televisions to homes in the near future. The company is also hoping to make other products with 3D, like laptops and PS3 "The 3D train is on the track, and we are ready to drive it home," said the President. 3D movies and TV programs are fun to watch, but do you know how they are made? It is much easier to understand if we do an experiment. Hold one of your fingers up at arms length and close one eye. Then try closing the other eye. As you switch between open eyes, you should see your finger "jumping" left and right against the background. This happens because our two eyes are about 4cm away from each other. The separation causes each eye to see the world from a different angle. The brain puts these two views together. What you see becomes three-dimensional. 3D movies are made using two video cameras at the same time, which creates two different images. When the movie plays in a cinema, two projectors put the two images on the screen. With a pair of 3D glasses, the two images are separated and each image only enters one eye. Your brain puts the two pictures back together, and the pictures on the screen become three-dimensional. The passage is mainly about   _  .
what 3D technology needs what 3D movies are how 3D movies develops how 3D technology works
Question: Have you had this experience? You are watching a movie. A man is shooting on the screen. The picture is so real that you think he is shooting at you. Or a car is speeding on the screen and at one point you are afraid that it will hit you. Three-dimensional(3D)movies use special technology to make pictures seem more real and exciting than two-dimensional ones. The popular movie Avatar uses 3D technology. So far we can only see 3D movies in the cinema with a special screen and projector .But soon, we will be able to watch them in our living rooms. Last month, Woods Company told reporters that it plans to bring 3D televisions to homes in the near future. The company is also hoping to make other products with 3D, like laptops and PS3 "The 3D train is on the track, and we are ready to drive it home," said the President. 3D movies and TV programs are fun to watch, but do you know how they are made? It is much easier to understand if we do an experiment. Hold one of your fingers up at arms length and close one eye. Then try closing the other eye. As you switch between open eyes, you should see your finger "jumping" left and right against the background. This happens because our two eyes are about 4cm away from each other. The separation causes each eye to see the world from a different angle. The brain puts these two views together. What you see becomes three-dimensional. 3D movies are made using two video cameras at the same time, which creates two different images. When the movie plays in a cinema, two projectors put the two images on the screen. With a pair of 3D glasses, the two images are separated and each image only enters one eye. Your brain puts the two pictures back together, and the pictures on the screen become three-dimensional. The passage is mainly about   _  .
A. what 3D technology needs
B. what 3D movies are
C. how 3D movies develops
D. how 3D technology works
Answer: