XBOX 360 Kinetic, RoboSapien, WiiParty, theseare just a few of the modern toys sold in recent years. But some of the most populartoys are actually quite old.

Gameshave been around for thousands of years. In 4000 B. C, Babylonians played a boardgame that was similar to chess. Yo-yos made of stone were first used in ancientGreece around 1000 B C. And kites appeared in China around the same time.

    Another famous game is Scrabble. It was inventedby an architect in the 1930s, but it didn't get popular until 1953 And since then,more than 100 million sets have been sold worldwide.

    As you can imagine, toys and games are a multi-billion-dollarindustry. Mr. Potato Head, the first toy advertised on TV, grossed more than $4million in its first year. Play-Doh made its inventor Joseph McVicker a millionaireby his 27th birthday, while Mattel sells 1. 5 million Barbie dolls each week (that'stwo dolls each second!).

    Some toys go out of fashion, but then becomepopular again, such as Rubik's Cube. Research says parents are increasingly choosingto buy toys they remember from their own childhood.

    These days, toys are not just for fun. RoboSapienis a remote-controlled robot that was launched in 2004. He can walk, turn aroundand do other poses. RoboSapien was designed by Mark Tilden, who once created robotsfor NASA space missions. He expected the toy to be used mostly by and scientists,but almost 2 million RoboSapiens have been sold worldwide since its launch as atoy?

    Fancy a game anyone?

The polluted 1 you're breathing could be slowly killing you, according 2 the World Health Organization, about 3 people die young from the polluted air every year. Air pollution is a huge problem for us all.

Smog is a combination(组合) of fog and smoke. PM2.5 is one of the 4 parts of smog, and it 5 the greatest r isk to human health. Beijing is one of the worst polluted 6 in China . It is said that only five days were not covered by heavy sm og in Beijing in the whole 7 of January in 2013. Its concentration(浓度)reached a record high of 993 on January 12, almost 50 8 the World Health Organization's standard.

9 smog can happen in any busy city, it's a particular problem in places such as Los Angeles,Smog becomes serious across China, especially in Beijing, largely 10 the high traffic levels, the large amount of coal burning, and the low quality of gas(汽油).

The sm og has made people in Beijing worry about their 11 . Many are choosing to travel out of the city 12 the thick smog, while others are buying air purifiers (空气净化器)to make indoor air clean. When the air is harmful, the government suggests people avoiding outdoor 13 . Officials have also closed some factories and ordered some government cars off the road. And they have made rules to stop new cement(水泥) and steel factories 14 opening.

All of us should play a part to 15 the environment for ourselves and our children. Also, the government should make rules to stop pollution.

China's new hit TV show To the Wonder(《我的阿勒泰》) has made Altay a popular place {#blank#}1{#/blank#}(在其中) young people. Altay {#blank#}2{#/blank#}(属于) to Xinjiang and it's like a place out of this world. {#blank#}3{#/blank#}(不管) you are a nature lover or a culture lover, it really has something for everyone.

This TV show tells the story of Li Wenxiu, a young woman from Altay. She didn't {#blank#}4{#/blank#}(成功) in becoming a writer, and {#blank#}5{#/blank#}(返回) to Altay to live with her mother. She then found the meaning of life and her love in her {#blank#}6{#/blank#}(家乡).

" Once we' ve seen the world and met our material needs, we started to look inside {#blank#}7{#/blank#}(我们自己), to search for a sense of peace and satisfaction and to {#blank#}8{#/blank#}(领会; 认识到) our self- worth(自我价值)," Teng Congcong, director of the TV show, told New Weekly magazine.

Since the TV show came out on May 7, tourism has {#blank#}9{#/blank#} (发展) rapidly in Altay. Many tourists want to go to this {#blank#}10{#/blank#}(有魔力的) place, enjoying the beautiful views.

To celebrate our 10th birthday, we are having a big sale!

Don't miss our amazing events in our birthday month!

Spend over $50 and get a chance to win a $10 gift card. Spend over $100 and get a chance to win prizes, from Borges membership to Taylor Swift's concert tickets!

Here are some encyclopedias for you to read in our online library. 

The Columbia Encyclopedia (Sixth Edition): An English-language dictionary containing more than 51, 000 topics, the Columbia Encyclopedia provides trusted facts and information. More than 200people make great efforts for depth and accuracy （精确） of the encyclopedia. Its topics are complete and clear. 

Medical encyclopedias: Online medical encyclopedias are for doctors, educators and students. The library of free medical encyclopedias contains a variety of trusted facts that cover medical conditions, medicals symptoms（症状），and medical causes of health-related problems. 

Computer encyclopedias: Our online library of computer encyclopedias is very useful whether you're looking for in-depth research or just learning about computer technology. The computer encyclopedias include topics like computer science, computer science and engineering, and computer science and technology. 

Science encyclopedias: Our online library of science encyclopedias covers a variety of topics from biology, psychology, and chemistry to religion and science discoveries. Our online science encyclopedias for kids are a big help for school research projects and science experiments. 

You've probably been told many times that exercise is good for your health, and it's believed that more is naturally better. But there comes a point. Is it possible to overdo it?

The first thing to ask yourself is"Why are you exercising?" if you're wondering whether you've exercised too much. "Once you get past five hours of energetic exercise every week, you're not exercising for health; you're exercising for performance. And it's possible to make your body too tired to recover(恢复), " said Kristen Dieffenbach, an exercise scientist. 

You exercise, and your body can get healthier, stronger and faster. These improvements don't happen during the exercise itself, but happen during the recovery period. 

As long as your body is able to keep up with this repair work, your exercise will continue to help your performance. But when the stress from your exercise builds up more than your capacity(容量) to recover, you are exercising too much. 

What makes things difficult is that the line between training hard and overtraining is unclear. The most important signs come from your feelings of happiness. Other classic signs of overtraining include trouble sleeping, feeling tired and being able to catch colds. 

If you find that you're having to push yourself to do exercise you used to enjoy, or are feeling guilty(内疚的) about not exercising enough, those are other signs that you've overdone it.