It is not a secret {#blank#}1{#/blank#} trees are vital to our life. They provide us with food, wood and most {#blank#}2{#/blank#} (important), oxygen. Now there is one more thing we can add to this list—blocking out harmful bacteria from water.

    The discovery {#blank#}3{#/blank#} (make) by a team {#blank#}4{#/blank#} (consist) of scientists from the Massachusetts Institute of Technology (MIT) and high school students {#blank#}5{#/blank#} were seeking a natural water filter(过滤)—one that would help communities in developing countries that do not have {#blank#}6{#/blank#} (accessible) to modern water filter systems.

    The {#blank#}7{#/blank#} (research), led by Professor Rohit Karnik, decided to turn{#blank#}8{#/blank#} trees for help, because they could allow liquid to flow through, while blocking out air bubbles.

    They began by cutting 1.5-inch-wide sections of tree bark from the branches of a white pine tree. The people related then tested the wood's filtering ability by pouring water containing red dye particles of different sizes through. To their {#blank#}9{#/blank#} (amaze), they found that it was effective in trapping all the particles. Greatly {#blank#}10{#/blank#} (encourage), the team conducted another experiment, this time with water that contained bacteria. Sure enough, the sapwood held back 99% of the bacteria, allowing only 1% to flow through.

    I was very happy when my friend Mary came to visit me from England. Her destination {#blank#}1{#/blank#}(be) Beijing and the architectural heritage of China. In {#blank#}2{#/blank#} (prepare) for her visit she had attended a series of seminars on the history of China. {#blank#}3{#/blank#} (check) into the Holiday Inn, Mary settled in and began her tour of the capital city. Day in and day out she walked around the city, rejoicing in its abundant {#blank#}4{#/blank#}(culture) sites and experiencing the kindness of its people. However, after seeing the Ming Tombs, she was eager {#blank#}5{#/blank#} (make) a trip to Xi'an to see the terracotta warriors, {#blank#}6{#/blank#} is known as the eighth wonder of the world.

    Originally this had been an optional trip on her schedule, but unfortunately it was later cancelled {#blank#}7{#/blank#} some reason. She felt it was out of the question for her to visit China without {#blank#}8{#/blank#} (go) to see the terracotta warriors, so I helped her arrange a tour to Xi'an. It was {#blank#}9{#/blank#}outstanding success and Mary returned to England with wonderful {#blank#}10{#/blank#} (memory) of her holiday in China.

    Silk was not the only product to be transported along the Silk Road, {#blank#}1{#/blank#}other goods such as tea, medicinal herbs also being exported from China. Many merchants found instant wealth through the trade in luxury items．

    Rather than traveling the entire length of the Silk Road, each merchant traded goods along one section of the route, {#blank#}2{#/blank#} (buy) them in one town and then selling in another. The travelers and merchants also {#blank#}3{#/blank#} (carry) many ideas, philosophies and religions with them along the Silk Road. Of all these, Buddhism, {#blank#}4{#/blank#}came from India, had the greatest influence on Chinese culture. It{#blank#}5{#/blank#}(eventual) became China's primary faith, {#blank#}6{#/blank#}(widespread) than the original Chinese religions of Confucianism and Taoism．

    Silk Road trades traveled together in long caravans of camels. This mode of travel provided{#blank#}7{#/blank#}(protect) from robbers who might attempt {#blank#}8{#/blank#} (rob) the valuable goods being transported．The Silk Road was not only one single road, but{#blank#}9{#/blank#} whole collection of routes by which goods{#blank#}10{#/blank#} (transport) between the East and the West．

    Currently， both women and men {#blank#}1{#/blank#}(surround) by magazines and websites full of tips about dieting， exercise and fashion. Gone are the days {#blank#}2{#/blank#} all men had to think about wearing a nice suit to be smart and handsome. Things have changed.

    Now， a survey has suggested that 80% of men admit {#blank#}3{#/blank#} (be) unhappy about their body. The biggest body issues for {#blank#}4{#/blank#} (they) were beer bellies and lack of muscles. Some think it is because {#blank#}5{#/blank#} the pressure of influence of role models we see on TV and in magazines. People end up with a perception of {#blank#}6{#/blank#} the perfect body should look like. But not everybody wants to put in the effort to have perfect muscles like Arnold Schwarzenegger. An opportunistic designer has even invented a muscle­enhancing shirt {#blank#}7{#/blank#}(make) the buyer look more of a strong man．

    But Joe Warner，the former editor of Men's Fitness magazine， thinks the muscle­enhancing shirt is just {#blank#}8{#/blank#} trick. He thinks many people in the country are overweight and should accept they need to do more exercise {#blank#}9{#/blank#}(regular)．Exercise is always good. But we mustn't forget beauty is only skin deep. Character is {#blank#}10{#/blank#} (important) than appearance.