April will bring a new product– the Apple Watch into the market. Last week, the watch was firstly introduced by Tim Cook, Apple's CEO. The price of the watch is from $349 to $1,099, depending on its size and whether it is a sports or regular one. Apple engineers and designers have put in a lot of thought and hard work into creating this small screen on your wrist. The sensor(传感器)on the screen not only finds your finger, but also knows the difference between when you are tapping(轻触), and when you are pressing harder.

    The watch also has haptic feedback(触觉反馈). You can send personal messages to your friend —such as drawing a star or a special sign with your fingers, or tapping the watch, say 3 times, and your friend will receive those taps on their wrist.

    Besides telling the time, the watch will use 'Bluetooth' to connect with your iPhone and show calls or text messages that come in.

    According to Tim Cook, the watch may open up a whole new area of applications（应用） that we had never thought of. Some car factories like BMW have developed an app that allows its car owners to open their cars with the watch. A 'Hotels' app may allow you to open the door to your hotel room without worrying about losing the smart-card. And finally, even at the airport—passengers may be able to simply wave their wrist to check into their flight.

    The biggest use of the watch, however, is as your personal fitness coach. The watch can show your pulse (heartbeat) using a sensor at the bottom of the watch. It also has the same sensor as your iPhone, so it knows when you are moving, and also how much you are walking or running. It will remind you if you have been sitting for too long without taking exercise.

    The human brain is divided into two sides, or hemispheres, called the right brain and the left brain. The two hemispheres work together, but each one specializes in certain ways of thinking.

    Each side has its own way of using information to help us think, understand, and process informa—tion.The left side of the brain controls language. It is more verbal and logical. It names things and puts them into groups. It uses rules and likes ideas to be clear, logical, and orderly. It is best at speech, reading, writing, and math. You use this side of the brain when you memorize spelling and grammar rules or when you do a math problem.

    The right side of the brain is more visual and creative. It specializes in using information it receives from the senses of sight, sound, smell, touch, and taste. This side of the brain likes to dream and experiment. It controls your appreciation of music, color, and art. You use this side when you draw a picture or listen to music.Although we all use both sides of our brains, one side is usually stronger or dominant. Some people are more “left—brained,” and others are more “right—brained”. Our dominant side influ—ences the kinds of jobs and hobbies we have. Politicians, artists, architects, and musicians depend on their right brains. Accountants, engineers, doctors, and lawyers usually rely on their left brains.

    In earliest times, men considered lightning to be one of the great mysteries (神秘的事物) of nature. Some ancient peoples believed that lightning and thunder were the weapons (武器) of the gods.

    In reality, lightning is a flow of electricity formed high above the earth. A single flash of lightning 1.6 kilometres long has enough electricity to light one million light bulbs (灯泡).

    The American scientist and statesman, Benjamin Franklin, was the first to show the connection between electricity and lightning in 1752. In the same year he also built the first lightning rod (避雷针). This device (装置物) protects buildings from being damaged by lightning.

    Modern science has discovered that one stroke (闪击) of lightning has a voltage (电压) of more than 15 million volts (伏特). A flash of lightning between a cloud and the earth may be as long as 13 kilometers, and travel at a speed of 30 million meters per second.

    Scientists judge that there are about 2,000 million flashes of lightning per year. Lightning hits the Empire State Building in New York City 30 to 48 times a year. In the United States alone it kills an average (平均数) of one person every day.

    The safest place to be in case of an electrical storm is in a closed car. Outside, one should go to low ground and not get under trees. Also, one should stay out of water and away from metal fences. Inside a house, people should avoid open doorways and windows and not touch wires or metal things.

    With lightning, it is better to be safe than sorry?

    Every year on April 22, People all over the world celebrate Earth Day. It is a time to work to keep our earth clean. People plan projects to clean up the land, air and water.

    U.S. Senator Gaylord Nelson first thought of the idea for Earth Day in 1962 when he saw polluted rivers and cities with smoke. He needed to get support from Americans to clean up the earth. Finally, on April 22, 1970, 20 million Americans celebrated the first Earth Day! Now many countries around the world celebrate it, and you can, too.

    How can you celebrate Earth Day? Here are a few ideas:

    Join a clean-up project-Clean up your street or a favorite beach.

    Save energy-Turn off the lights when you leave a room, and use public transportation.

    Use less water.

    Reduce(减少)/ Reuse/ Recycle ― Practice the three Rs: First, reduce how much you use. Then reuse or recycle what you can.

    You can make a difference on Earth Day and every day!