Have you ever {#blank#}1{#/blank#} (stay) up late? If so, you know that not getting enough sleep can make you tired. Not sleeping enough can also make {#blank#}2{#/blank#} hard to think clearly the next day.

    Sleep scientists have long known that getting a good night's sleep is of great {#blank#}3{#/blank#} (important). It helps kids to be able {#blank#}4{#/blank#} (do)their best during the day.

    A recent study shows that sleep {#blank#}5{#/blank#} (help) improve problem-solving skills and {#blank#}6{#/blank#}(create) thinking. For the study, two groups of students answered {#blank#}7{#/blank#} math problems. The group that slept for eight hou rs solved the problem {#blank#}8{#/blank#} (correct) more often than the group that did not get enough sleeping.

    While you sleep {#blank#}9{#/blank#} night, your brain is busy doing its “homework”. It sorts out (整理) the information {#blank#}10{#/blank#} you get in the day. Getting enough sleep each night can improve your thinking ability. That will surely help you do your best at school. Experts say that, in return, can lead to better grades.

    In the past, it took a long time for people to find someone. Nowadays, however, {#blank#}1{#/blank#} the help of online communities, people can get their search {#blank#}2{#/blank#} (do) within a short period of time. All they need to do {#blank#}3{#/blank#} (be) get online and upload a picture of the person they are looking for, or share some basic information about this person. Because of the “footprints” people {#blank#}4{#/blank#} (leave)

    online, other Internet users are usually able to find anyone{#blank#}5{#/blank#}they are interested in.

    One example of this is a man who beat a dog cruelly. His {#blank#}6{#/blank#} (violent) was recorded and uploaded online. In a very short time, the man was reported to an animal rescue team. In the end, he was punished and made to apologize. {#blank#}7{#/blank#} example involves a college student who refused {#blank#}8{#/blank#} (clean) up after her dog on the subway. Netizens revealed her personal information in order to punish her. {#blank#}9{#/blank#} (wide) blamed for her behavior, this girl left college eventually. Many people thus began to debate {#blank#}10{#/blank#} a “witch-hunt” like this went to far or not.

    The Great Wall of China is more than 6,000 kilometres long. It winds {#blank#}1{#/blank#} (it) way from west to east, across deserts, over mountains, through valleys{#blank#}2{#/blank#}at last it reaches the sea. The Great Wall has a history of over twenty centuries. The first part of it {#blank#}3{#/blank#}(build) during the Spring and Autumn period. During the Qin Dynasty, {#blank#}4{#/blank#}(keep) the enemy out of his empire, Emperor Qin Shi Huang had all the walls {#blank#}5{#/blank#}(join) up. Thus, the Great Wall came into being. The Great Wall is wide enough at {#blank#}6{#/blank#}top for five horses or ten men to walk side by side. Along the wall are watchtowers, {#blank#}7{#/blank#}soldiers used to keep watch. Fires were lit on the towers as a {#blank#}8{#/blank#} (warn) when the enemy came.

    It was {#blank#}9{#/blank#}(extreme)difficult to build such a wall in the ancient days without any modern machines. All the work was done {#blank#}10{#/blank#}hand. Thousands of men died and were buried under the wall they built. The Great Wall was made not only of stone and earth, but of the flesh and blood of millions of men.

    Beijing opera or Peking opera is a form of Chinese opera {#blank#}1{#/blank#}(combine) music, vocal performances, dance and so on. It{#blank#}2{#/blank#} (arise) in the late 18th century and became {#blank#}3{#/blank#} (full) developed and recognized by the mid-19th century. The form was extremely popular in {#blank#}4{#/blank#} Qing Dynasty court and has come to be regarded as one of the {#blank#}5{#/blank#} (culture) treasures of China. Major performance troupes (剧团，戏班子）are based in Beijing and Tianjin in the north, and Shanghai in the south. Also {#blank#}6{#/blank#} (preserve) in Taiwan, the art form is still of great importance to people there.

    {#blank#}7{#/blank#} (perform) of Peking opera use the skills of speech, song, dance, and combat in movements that are symbolic and suggestive. Above all else, the skill of performers {#blank#}8{#/blank#} (evaluate) according to the beauty of their movements. The music of Beijing opera can be divided {#blank#}9{#/blank#} the Xipi and Erhuang styles. The repertoire (全部曲目）of Beijing opera includes over 1,400 works, {#blank#}10{#/blank#}characters are based on Chinese history, folklore, and, increasingly, contemporary life.

    Polar bears are suffering in a {#blank#}1{#/blank#} (warm) world than ever before. Polar bears live in environments too cold for most animals. During much of the year, they live and hunt on the{#blank#}2{#/blank#} (freeze) Arctic sea ice. Nature has prepared them for the cold conditions but nothing has prepared the bears for the danger that {#blank#}3{#/blank#} (threat) the only home they know. The scientists have drawn a {#blank#}4{#/blank#} (conclude) that the polar bears' world is melting. Studies show that the polar ice has reduced{#blank#}5{#/blank#}9.8% every 10 years since 1978. Now about 20,000 to 25,000 polar bears live in the Arctic. Polar bears depend on the sea ice for their {#blank#}6{#/blank#} (survive). "The sea ice is more than just this platform that the bears walk over." As Andrew Derocher, a scientist who studies North American polar bear populations puts {#blank#}7{#/blank#}, "Only if polar ice melts quite slowly {#blank#}8{#/blank#}they survive on the earth." Some melting and refreezing of the polar ice is natural. {#blank#}9{#/blank#} in a warmer world, these cycles speed up, and bears have less time to hunt. Normally, they have three months in the spring when they gain more weight. The extra fat is used later, {#blank#}10{#/blank#} the bears are not actively hunting.

    There is a wonderful story about Jimmy Durante, {#blank#}1{#/blank#}is one of the great singers in the twentieth century. One day, when {#blank#}2{#/blank#}(ask)to be part of a show for some old World War II soldiers, Jimmy said he could afford only a few minutes and {#blank#}3{#/blank#}he would come if they wouldn't mind his singing one short song and immediately leaving for his next appointment. Of course, the show's director agreed happily.

    But when Jimmy got on stage, something {#blank#}4{#/blank#}(surprise) happened. He went through the short song and then stayed. The applause grew louder and louder and he kept staying. Pretty soon, he had been on stage{#blank#}5{#/blank#}fifteen, twenty, and then thirty minutes. One of his assistants behind the stage stopped him and said, “I thought you had to go after a few minutes. What happened?” Jimmy answered, “I did have to go, but I can show you the reason{#blank#}6{#/blank#} I stayed. You can see for yourself if you look at the front row.” In the front row {#blank#}7{#/blank#}(be) two men, both of {#blank#}8{#/blank#}had lost an arm in the war. {#blank#}9{#/blank#}had lost his right arm and the other had lost his left. Together, they were able to clap, and that was exactly{#blank#}10{#/blank#} they were doing, loudly and cheerfully.