How fit are your teeth? Are you lazy about brushing them? Never fear: An inventor is on the case. An electric toothbrush senses how long and how well you brush, and it lets you track your performance on your phone.

    The Kolibree toothbrush was exhibited at the International Consumer Electronics Show in Las Vegas this week. It senses how it is moved and can send the information to an Android phone or iPhone via a Bluetooth wireless connection.

    The toothbrush will be able to teach you to brush right (don't forget the insides of the teeth!) and make sure you're brushing long enough. “It's kind of like having a dentist actually watch your brushing on a day-to-day basis,” says Thomas Serval, the French inventor.

    The toothbrush will also be able to talk to other applications on your phone, so developers could, for instance, create a game controlled by your toothbrush. You could score points for beating monsters among your teeth. “We try to make it smart but also  fun,” Several says.

    Serval says he was inspired by his experience as a father. He would come home from work and ask his kids if they had brushed their teeth. They said “yes,” but Serval would find their toothbrush heads dry. He decided he needed a brush that really told him how well his children brushed.

    The company says the Kolibree will go on sale this summer, for $99 to $199, developing on features. The U.S. is the first target market.

    Serval says that one day, it'll be possible to replace the brush on the handle with a brushing unit that also has a camera. The camera can even examine holes in your teeth while you brush.

    World Expo 2010 will be held in Shanghai. It will last from May 1st to October 31st, 2010. The Expo site covers a total area of 5.28 km². It spans(横跨) both sides of the Huangpu River, with 3.93 km² in Pudong and 1.35 km² in Puxi. There are five functional zones marked A, B, C, D and E. Each of them has different functions.

    Zone A will host the national pavilions(国家馆) of Asian countries except southeast Asian ones.

    Zone B will be home to the China Pavilion(中国馆) and Oceania (大洋洲的) countries, Pavilions for International Organizations, Theme Pavilions(主题馆), Expo Centre, and Performance Centre etc.

    Zone C will host the national pavilions of European, American and African countries. A large public amusement park will be built at the entrance of this zone.

    Zone D is home to Corporate Pavilions(企业馆), the land is one of the original places of modern China's national industry. So some of the old industrial buildings will be kept and renovated(修复) into Expo pavilions.

    Zone E will host stand-alone(独立的) Corporate Pavilions, Urban Civilization Pavilion (城市文明馆), and Urban Best Practices Area.

    Mountaineers have noted that as they climb, for example, up to the 12,633­foot Humphreys Peak in Arizona, plant life changes greatly. In the Sonoran Desert, one climbs into a pine forest at 7,000 feet and a treeless tundra(冻土带) on the top of the mountain. It may seem that plants at a given altitude are associated in what can be called “communities” －groupings of species. The idea is that over time, plants that require particular climate and soil conditions come to live in the same places, and are frequently to be found together. Scientists study the history of plant life and build up a picture of how groups of plants have responded to climate changes and how ecosystems develop. But are these associations, which are real in the present, permanent?

    A great natural experiment took place on this planet between 25,000 and 10,000 years ago, when small changes in the earth's orbit caused great sheets of ice to spread from poles. These glaciers(冰川) covered much of North America and Europe to depths of up to two miles, and then, as the climate warmed, they retreated. During this retreat, they left behind newly uncovered land for living things to occupy, and as those living things moved in they laid down a record we can read now. As the ice retreated and plants started to grow near a lake, they release pollen(花粉). Some would fall into the lake, sink to the bottom and mix with the sand. By drilling into the lake bottom it is possible to read the record of the plant life around the lake. The fossil record seems clear; there is little or no evidence that entire groups of plants moved north together. Things that lived together in the past don't live together now, and things that live together now didn't live together in the past. Each individual living things moved at its own pace. The fossil record seems to be telling us that we should be thinking about preserving species by giving them room to move about－to respond to environmental changes.

    One of my neighbors used to have a beautiful tree in her front yard. Her dad had planted it for her when it was nothing more than a twig(树枝) and several years later it started to shoot towards the sky with amazing speed. Soon it blessed her with cooling shade in the summer and glorious, golden leaves in the fall.

    When the two-day snowstorm struck our town, heavy snow fell on the tree's branches that were still full of leaves. The weight split that lovely tree down the middle. It was so sad seeing half of it laying on the ground after the storm. When I talked to my neighbor later, she said that the damage had been too much and that the entire tree would have to be cut down. Thankfully she had saved a few saplings(树苗) from it that she hoped to replant in the future.

    Still, it was a shock to drive by her house the other day and see nothing but a stump in her front yard. I missed that tree. I missed its beauty, its leaves shinning in the afternoon sun. I missed seeing its limbs reach towards the heavens. I thought that the stump would be a sad reminder of its loss for a long time to come. My wonderful neighbor, though, had another plan. When I drove by her home today I saw a tiny bird feeder sitting on that stump and a colorful songbird having its dinner. It was such an affirmation of life. It was such a joy to see. I could feel my heart smile.

    Life by its very nature is a mixed bag. It hands us beauty and tragedy, love and loss, pleasure and pain. What we do with it, however, is up to us. We can let it split us in two, or we can use even its hardest times to make our souls stronger and our hearts more loving. We can spend it complaining or we can use it to help others.

    “Sesame Street” has been called “the longest street in the world”. That is because the television program by that name can now be seen in so many parts of the world. That program became one of American's exports soon after it went on the air in New York in 1969.

    In the United States more than six million children watch the program regularly. The viewers include more than half the nation's pre-school children, from every kind of economic, racial, and geographical group.

    Although some educators object to certain elements in the program, parents praise it highly. Many teachers also consider it a great help, though some teachers find that problems arise when first graders who have learned from “Sesame Street” are in the same class with children who have not watched the program.

    Tests have shown that children from all racial, geographical, and economic backgrounds have benefited from watching it. Those who watch it five times a week learn more than occasional（偶然的）viewers. In the US the program is shown at different hours during the week in order to increase the number of children who can watch it regularly.

    The programs all use songs, stories, jokes, and pictures to give children a basic understanding of numbers, letters and human relationships. But there are some differences. For example, the Spanish program, produced in Mexico City, devotes more time to teaching whole words than to teaching separate letters.

    Why has “Sesame Street” been so much more successful than other children's shows? Many reasons have been suggested. People mention the educational theories（理论）of its creators, the support by the government and private（私人的）businesses, and the skillful use of a variety of TV tricks. Perhaps an equally important reason is that mothers watch it along with their children. This is partly because famous adult stars often appear on it. But the best reason for the success of the program may be that it makes every child watching feel able to learn. The child finds himself learning, and he wants to learn more.

My First Marathon（马拉松）

    A month before my first marathon, one of my ankles was injured and this meant not running for two weeks, leaving me only two weeks to train. Yet, I was determined to go ahead.

    I remember back to my 7th year in school. In my first P.E. class, the teacher required us to run laps and then hit a softball. I didn't do either well. He later informed me that I was ＂not athletic＂.

    The idea that I was ＂not athletic＂ stuck with me for years. When I started running in my 30s, I realized running was a battle against myself, not about competition or whether or not I was athletic. It was all about the battle against my own body and mind. A test of wills!

    The night before my marathon, I dreamed that I couldn't even find the finish line. I woke up sweating and nervous, but ready to prove something to myself.

    Shortly after crossing the start line, my shoe laces(鞋带) became untied. So I stopped to readjust. Not the start I wanted!

    At mile 3, I passed a sign: ＂GO FOR IT, RUNNERS!＂

    By mile 17, I became out of breath and the once injured ankle hurt badly. Despite the pain, I stayed the course walking a bit and then running again.

    By mile 21, I was starving!

    As I approached mile 23, I could see my wife waving a sign. She is my biggest fan. She never minded the alarm clock sounding at 4 a.m. or questioned my expenses on running.

    I was one of the final runners to finish. But I finished! And I got a medal. In fact, I got the same medal as the one that the guy who came in first place had.gkstk

    Determined to be myself, move forward, free of shame and worldly labels(世俗标签), I can now call myself a ＂marathon winner＂.