For several billion years after the "Big Bang", the earth was still just a cloud of dust. What it was to {#blank#}1{#/blank#} was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe. The earth became so {#blank#}2{#/blank#} that it was not clear whether the shape would last or not.

     {#blank#}3{#/blank#} eastward, you'll pass mountains and thousands of lakes and forests, as well as wide rivers and large cities. Some people have the idea {#blank#}4{#/blank#} you can cross Canada in less than five days, but they forget the fact that Canada is 5500 kilometers from coast to coast. Here in Vancouver, you're in Canada's warmest part. People say it is Canada's most beautiful city. {#blank#}5{#/blank#} by mountains and the Pacific Ocean. Its population is increasing rapidly. The coast {#blank#}6{#/blank#} of Vancouver has some of the oldest and most beautiful forests in the world.

    However, this was not easy. When they first arrived in Gombe in 1960, it was unusual for a woman to live in the froest. {#blank#}7{#/blank#} after her mother came to help her for the first few months {#blank#}8{#/blank#} she allowed to begin her project. Her work changed the way people think about chimps. For example, one important thing she discovered was that chimps hunt and eat meat. Until then everyone {#blank#}9{#/blank#} thought chimps ate only fruit and nuts. She also discovered how chimps communicate with each other, and her study of their body language helped her {#blank#}10{#/blank#} their social system.

    Diets have changed in China-and so too has its top crop. Since 2011,the country{#blank#}1{#/blank#}（grow）more corn than rice. Corn production has jumped nearly 125 percent over{#blank#}2{#/blank#}past 25 years, while rice has increased only 7 percent.

    A taste for meat is{#blank#}3{#/blank#}(actual) behind the change. An important part of its corn is used to feed chickens, pigs, and cattle. Another reason for corn's rise. The government encourages farmers to grow corn instead of rice{#blank#}4{#/blank#}(improve) water quality. Corn uses less water{#blank#}5{#/blank#}rice and creates less fertilizer(化肥) runoff. This switch has decreased{#blank#}6{#/blank#}(pollute) in the country's major lakes and reservoirs and made drinking water safer for people.

    According to the World Bank, China accounts for about 30 percent of total{#blank#}7{#/blank#}(globe)fertilizer consumption. The Chinese Ministry of Agriculture finds that between 2005-when the government {#blank#}8{#/blank#} (start) a soil-testing program {#blank#}9{#/blank#} gives specific fertilizer recommendations to farmers - and 2011, fertilizer use dropped by 7.7 million tons. That prevented the emission(排放) of 51.8 million tons of carbon dioxide. China's approach to protecting its environment while {#blank#}10{#/blank#} (feed) its citizens "offers useful lessons for agriculture and food policymakers worldwide." says the bank's Juergen Voegele.

    For many young people, {#blank#}1{#/blank#} (go) to university is one of the most important {#blank#}2{#/blank#}(stage) of their lives. It is the time when young people will move out of {#blank#}3{#/blank#} (they) home to live with other people, often strangers. {#blank#}4{#/blank#}(especial) in the US, people often travel very far from home to study. It is a time to be {#blank#}5{#/blank#} (dependence).

    At university, you {#blank#}6{#/blank#} (teach) by lectures and professors who are leading figures in their study. The opportunity to learn from and to discuss with them is {#blank#}7{#/blank#} drives some people to apply to university. Students are required to choose a major that they wish to study. Apart {#blank#}8{#/blank#} the academic benefit, life at university can also allow students {#blank#}9{#/blank#} (develop) their interests in many fields.

    Therefore, university is a place {#blank#}10{#/blank#} you attain knowledge, to develop your values and accept those who may be different.

    Agricultural experts say crop diversity is important to feed the{#blank#}1{#/blank#}(increase) population of our planet. They say having a large variety of plants also{#blank#}2{#/blank#}(help) to protect against possible crop diseases and future crises. But many experts say the number has decreased sharply during the past century.

    One of the world's {#blank#}3{#/blank#}(large) seed conservation projects has predicted further losses. The Millennium Seed Bank Partnership is warning that up to one hundred thousand plant species could {#blank#}4{#/blank#} (permanent) disappear. The rich collection of genes{#blank#}5{#/blank#} decide their qualities would disappear with them.

    Many experts blame climate change and loss of habitat, normal growth area, for damaging plant life. They say human{#blank#}6{#/blank#}(activity) and poorly planned, overly heavy use of land also are responsible. Modern business farming is responsible{#blank#}7{#/blank#}loss of farmers' traditional crop varieties. The "Green Revolution" of the twentieth century changed agriculture. Some experts say the use of modern commercial farming methods saved millions of people from{#blank#}8{#/blank#}(starve). Farmers planted, watered, and fertilized their crops with the help of machines. They treated their fields with chemicals{#blank#}9{#/blank#}(control) diseases and insects. Harvests grew larger and higher quality,{#blank#}10{#/blank#} another result was that some traditional crops were lost. Damage to the environment over the past century makes people believe that crop diversity also suffered.

    Ever wondered how many calories are in the human body? Or ever wondered why old people have {#blank#}1{#/blank#} (big) ears than they used to? The winners of Ig Nobel Prizes (搞笑诺贝尔奖) have got the answers.

    He Ig Nobel Prizes, founded in 1991, are to honor achievements {#blank#}2{#/blank#} first make people laugh, and then make them think, The ceremony {#blank#}3{#/blank#} (take) place at Harvard University every year. Winners' acceptance {#blank#}4{#/blank#}(speech) are limited to 60 seconds, {#blank#}5{#/blank#} (strict) policed by an eight-year-old girl.

    The honored research might seem ridiculous {#blank#}6{#/blank#} first sight, but that doesn't mean it lacks scientific value. For example, the research in 2006 on why dry spaghetti tends to break into more than two pieces was important {#blank#}7{#/blank#} (discover) failure in bridge spans (跨度) or human bones And a follow-up paper {#blank#}8{#/blank#} (publish) by MIT physicists several years later. But people are more likely to read about {#blank#}9{#/blank#} (break) spaghetti than to read an academic paper. Even when there is no immediate usefulness, {#blank#}10{#/blank#} is still good to encourage people to observe and think.

    I wonder if it's because I haven't been able to be outdoor for so long {#blank#}1{#/blank#}I've grown so crazy about very everything {#blank#}2{#/blank#} (do) with nature. I can well remember that there was{#blank#}3{#/blank#} time when a deep blue sky, the song of the birds, moonlight and flowers could never have kept me spellbound. That {#blank#}4{#/blank#}(change) since I was here.

    One evening when it was so warm, I stayed awake{#blank#}5{#/blank#} purpose until half past eleven in order to have a good look at the moon by {#blank#}6{#/blank#}. But as the moon gave far too much light, I didn't dare open a window. Another time five months ago, I happened to be upstairs at dusk when the window was open. I didn't go downstairs {#blank#}7{#/blank#}the window had to be shut.

    Sadly …I am only able to look at nature {#blank#}8{#/blank#} dirty curtains hanging before very dusty windows. It's no pleasure {#blank#}9{#/blank#} (look) through these any longer because nature is one thing that really must {#blank#}10{#/blank#} (experience).