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(图像)from the movie look as if they were coming straight towards 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. 3D technology can make TV and movies are more exciting. However, 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 people with eye problems to get dizzy(头晕的) or have 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.

    This is a home of the future, a "smart home", where technology can do almost everything. Imagine we are in the year 2050, ①the computer wakes Tom up in themorning as usual. In front of him is a to-do list of the important events for the day, and it is provided by the computer too. According to Tom's request, the computer serves a list of possible dishes. All the dishes are nice.

    As Tom eats breakfast, the computer reminds him to reply to Lucy. Before Tom finishes his next bite, Lucy's computer receives the message. Then Tom goes to the supermarket. The store's system checks his car when he drives to the pickup area and greets him by name. "Good morning, Tom! Your order is in Case4. Thank you for shopping.'' When Tom removes his order from Case 4, all trades are completed automatically(自动地)over the information superhighway. That is, the money is electronically paid into the bank. Soon after arriving at the office, Tom reads another message from Lucy, telling him that she will go to dinner with him.

    The smart home can also do many other things:

    ◆Find things like keys and mobile phones.

    ◆②        (打开或关闭)machines and lights with your voice.

    ◆Clean your home from clothes to buildings automatically.

    ◆Record everything and everyone entering and leaving the house.

    ◆Take care of each member of the family, young or old.

    ③With the development of technology, the smart home will come true in the future. It is sure to play an important part in our life.

The seasons on Earth

    The Earth that we live on is moving all the time. The Earth turns around itself once every 24 hours. This gives us day and night. The Earth also travels around the Sun once every year. This gives us the four seasons. We have spring and summer when our part of the Earth leans (倾斜) towards the Sun. We have autumn and winter when our part of the Earth leans away from the Sun.

    In many places on Earth, there are four seasons in a year. But in some places there are only two seasons. For example, near the North Pole (北极) there are only winter and summer. The winter nights are long. For more than two months you can't see the Sun, even at noon. The summer days are long. For more than two months the Sun never sets, and there is no night. In the tropics (热带地区) there are also two seasons: a rainy season (wet season) and a dry season.

Why Do People Blink (眨眼) Their Eyes?

    People blink their eyes tens of thousands of times every day. Scientists have long believed blinking was an involuntary movement and served mainly to keep the eyeballs wet. But a new study suggests it has a more important purpose.

    An international team of scientists from the University of California at Berkeley studied the blinking of human eyelids. The journal Current Biology published their findings. The team said they found that blinking "repositions our eyeballs so we can stay focused" on what we are seeing. They said that when we blink our eyelids, the eyes roll back into their sockets—the bony area that surrounds and protects the eyes. However, the researchers found the eyes don't always return to the same position (位置). They said this causes the brain to tell the eye muscles (肌肉) to reorganize our eyesight.

    Gerrit Maus is the lead writer of the report. He serves as an assistant professor of psychology at Nanyang Technological University in Singapore. Maus said, "Our eye muscles are quite sluggish (迟缓的) and imprecise (不精确的), so the brain needs to constantly adapt (改编) its motor signals to make sure our eyes are pointing where they should be. Our findings suggested that the brain measures the difference in what we see before and after a blink, and orders the eye muscles to make the needed corrections." The researchers said that without such corrections our surroundings would appear unclear and even jumpy. They said the movement acts "like a steadicam (摄影稳定器) of the mind."

    The researchers said they asked volunteers to sit in a dark room while storing at a small dot on a flat surface. They used special cameras to follow the volunteer's blinks and eye movements. After each blink, the dot was moved one centimeter to the right. The volunteers did not notice this, but the brain did. It followed the movement and directed the eye muscles to refocus on the dot. After the dot was moved in this way 30 times, the volunteers' eyes changed their focus to the place where they predicted it would be.

    Professor Maus said. "Even though the volunteers did not consciously register that the dot had moved, their brains did, and adjusted (调整)with the corrective eye movements. These findings add to our understanding of how the brain constantly adapts to (适应) changes directing our eye muscles to correct for errors in our bodies' own hardware."