18．
Have you seen Avatar（《阿凡达》）？It's a popular 3D movie，and you may have to wear 3D glasses to see it．The 3D glasses make the images（图象）from the movie look as if they are coming straight at you．
More and more 3D movies are coming to theaters．Some say that 3D TV sets will come into our homes in the near future．Three-dimensional technology can make TV and movies more exciting．But people with eye problems may get headaches if they spend too much time watching 3D movies．Why？
When we look at an object（物体），each eye sees it at a different angle（角度）．Our eyes send the two images to our brain（大脑），and the brain puts them together.3D technology uses two film projectors（投影机）．One projects a left eye image and the other projects a right eye image.3D glasses allow us to see a different image in each eye．So，when we are watching a 3D movie，our brain can't put together the images sent to our eyes．The brain needs to work harder at"reading"the images．That makes it easier for these people to get dizzy（头晕的） or develop headaches．A famous eye doctor said if your eyes can't focus（聚焦） on the same object at once，you will have trouble watching 3D movies．
66．According to the passage，Avatar is aC．
A．digital cameraB．digital TV setC．3D movie
67．The 3D glasses can make the images from the movieB．
A．look more beautiful than usual
B．look as if they are coming straight at you
C．look as if they are far away from you
68．People will haveC in their homes in the near future．
A．3D computersB．3D phonesC．3D TV sets
69．When we look at an object，B．
A．each eye sees the object at the same angle
B．our brain puts the two different pictures together
C．there will be two film projectors in our eyes
70．If you wear a pair of 3D glasses，A．
A．you will see different images in both eyes
B．Your brain can't work at all
C．the images can be put together easily by your brain．
