When you watch 3D movies or TV, you have to wear a special pair of glasses. The 3D glasses make the images from the screen look like they are there in the room with you.

    Three-dimensional, or 3D, means having three dimensions（维度）: width, height and depth. 3D technology（技术） is based on the way the human brain（大脑） and eyes work. Because the pupils of a person's eyes are about 6.5era apart（分开）, when we look at something, each eye sees,it from a different angle（角度）. Our eyes send the two images to our brain, and the brain puts them together. The small difference between the image from the right eye and the image from the left eye allows us to see depth.

    When we view pictures and television in two dimensions, each eye gets the same information. That is because the image has no real depth, and there is only one of viewing it. So the goal of 3D technology is to get a different image into each of the viewer. It uses two film projectors. One projects a left eye image and the other projects a right image. The 3D glasses allow us to see a different image in each eye.

    While watching 3D films, we feel that we are in the same environment as the things we're watching. However, it also has its disadvantages. The 3D glasseswork by controlling the amount of light that reaches the eyes. It makes the screen look darker. What's more, people with eye problems may get headaches if they spend too much time watching 3D movies，because their brains need to work harder to "read" the images.

短文理解  阅读下列短文，从每题所给的A、B、C三个选项中，选出最佳选项回答问题或完成句子。

      It was a Christmas night. I was an unlucky nurse who had to work on such a beautiful festival. When I was complaining（抱怨）about it, three people appeared at my desk — a tired woman and two children.

    "Are you all sick?"I asked doubtfully because they seemed all right.

    "Yes,"the woman answered weakly and lowered her head.

    But when they started to present their problems, things became unclear. One child had a fever, but his temperature was OK. The other child had an earache, but she could not tell me which ear hurt. It seemed that the mother was pretending（假装）to cough.

    Something was wrong. But I only explained that it might take a while before a doctor could meet them. "Take your time, please,"said the mother. I checked their charts — no address. Suddenly I knew, they were homeless while the hospital was warm.

The family huddled（蜷缩）together under the Christmas tree, smiling and talking with each other sweetly. Quietly, I went back to the nurses'station and told them what happened in the waiting room. It was just like God sending us a gift on Christmas Day. The nurses' station suddenly came back to life. All the nurses went into action for "a Christmas emergency（急诊）".

    We took out our meals for our Christmas "patients". We also put together oranges and apples as presents. We tried to exceed the needs of a family who only wanted a warm place on Christmas night. Later, the little girl kissed me and said, "Thanks for being our angel（天使）."

    Little Bob was born in a poor village in New York. His father has been ill for a long time and can not do any housework at all. Bob's mother is very busy with the housework besides working. Bob understands how hard his mother works, and he always helps her with some housework. Though he has too much housework to do, his mother is still very strict with him. There are some family rules for Bob.

    He must take good care of his things in his room and keep them tidy. If he makes them dirty, he must clean them up at once.

    He is allowed to keep a parrot, a cat and a dog, but he must feed them often and give them water by himself every day. After school, he is allowed to play with his pets for a short time.

    As for his clothes, he isn't allowed to choose his own clothes. When his clothes are dirty, he should wash them by himself.

    On school nights, he can't go out alone and only on weekends, he is allowed to watch TV. Sometimes Bob hates the rules so much that he wants to break them, but he thinks the rules his mother has made are good for him, so he faithfully obeys them.

阅读下面短文,根据短文内容完成下列各题。

    Sir Steven—Winner of 5 Olympic Gold Medals.

    "in 1997 I was found have developed diabetes (糖尿病）Believing the profession trained for the whole of my life ended, I felt very sorry. Then one of my friends said there was no reason why I should stop training and competing. That was it—the encouragement I needed. I could still be a winner if I believed in myself. I am not saying that it isn't difficult sometimes. But I wanted to prove to myself that I wasn't finished yet. Nothing is to stand in my way. "

    Karen Pickering—Swimming World Champion(冠军)

    "I swim 4 hours a day, 6 days a week. I manage that amount of work by putting it on top diary. This is the key to success—"you can't follow a profession in any field without being organized Make a list of what you believe you can achieve. Trust yourself, write down your for the day, however small they are, and you'll be a step closer to achieving them.

    Kristen Stewart—Actress

    "When things are getting hard, a voice inside my head tells me that I can't achieve anything. Then, there are other distractions, such as family or hobbies. The key is to give most of your attention to one thing. When I feel nervous, it helps a lot to repeat words such as focus, calm, peace, either out loud or silently in my mind. It makes me feel more in control and increases my confidence. This is a habit and is a powerful psychological(心理学的)tool."

    The relationship(关系) between teachers and students is an important part of school life. An Indian movie called Hichki tells the story of a teacher who helps some bad students and makes them better people. It is popular with lots of students now.

In Hichki, the main character is Naina Mathur. She has an illness(疾病) that makes her hiccup(打嗝) often. With her hard work, she gets her dream job as a teacher. But she has to teach a class of rebellious students. They laugh at Mathur in her first class.
    However, Mathur doesn't get angry(生气) with them. She tries her best to help every student. When they cause a small explosion (爆炸) and the school asks them to leave, Mathur still help them a lot. Little by little, Mathur wins the students' hearts. Under her care, the students start to study harder and become better and better.

    From the story, we know that a good teacher doesn't simply pass on knowledge(知识), but shows students how to be a good person. It also shows us that anyone can be successful, even if they have some kind of illness.