【正文】 t do its best to offer helpB. there is no good medical knowledge and skillsC. some countries can39。t allow the grass and trees to burn. As a result, today many forests have thicker vegetation(植被). Thicker vegetation means more fuel(燃料) for fires. Also, without fires from time to time, forests bee overcrowded and unhealthy. Some trees are dead. The dead wood then easily catches fire. So surprisingly, America has many more fires today partly because of its past firefighting practices.Scientists now understand that a fire can be a natural part of a healthy forest. As a result, countries like Australia allow more fires to burn naturally. Sometimes, firefighters even start fires to get rid of(去除) dead wood. Of course, they carefully control the fires. The fire thins out old trees. This allows sunlight to reach the ground. As a result, fires help new trees to grow. Therefore, if a fire is not a serious threat(威脅) to people, firefighters may let it burn naturally.68. Why did Russia have so many fires in one month in 2010?A. Because lightening spread the fire.B. Because there was much fuel for fires.C. Because there were not enough firefighters.D. Because it was unusually hot, dry and windy.69. What happens because of the traditional firefighting practices in the USA?A. There are fewer wildfires.B. Trees and grass bee thicker.C. The weather bees warmer and drier.D. Sunlight reaches the ground to help forests.70. What is the main idea of Paragraph 4?A. Fires are serious threats to human beings.B. Australian firefighters don39。ll know what is worth seeing and doing, so that you can make the most of your time at the museum. Decide what museum you will visit. There are so many different kinds of museums and you first need to find one that you like. It39。s love of tea is wellknown. When the British won control over mush of North America in the early 1700s, they brought their tea drinking habits with them. Tea quickly became the continents most popular drink. As tea could not be grown locally, just as in Britain, it was shipped into the country—mostly from India.In the early 1700s, the Britain government made a special deal with the East India Company, as an English trading pany. They agreed that no other pany was allowed to bring tea to Britain or any country controlled by Britain, including America. It was a great deal for the East India Company, since it meant that the pany could decide whatever price it wanted for its products. And it always decided on a high price!In North America, the local people did not like having to pay such high prices. Instead of overpaying for tea from the British, they turned to Dutch traders, who secretly brought tea to the country that was just as good—and much less expensive. Although this broke the law, the American people didn39。s energy, water and chemicals from the soil), they also produce waste which they return to the soil. Tiny animals in the soil eat this waste and they produce electrons—the building blocks of electrical energy. The UT team put special sticks inside the soil to capture the energy and keep it in the lamp39。Do you sleep well? If your answer is no, the following might help you.Set a certain bedtime and rising timeA certain bedtime and rising time can help you build up your body clocks. Set a bedtime which is good and natural for you. Don’t change your bedtime and rising time on weekends.Avoid exciting activities just before sleepingExciting activities get your thoughts running. At the same time, if you make tomorrow’s plan or read an exciting story before turning off the light, it doesn’t give you enough time to relax before you try to sleep.Keep the bedroom for sleeping onlyIt’s a bad habit for you to use your bedroom as a place to eat, watch TV, read, talk on the phone, or discuss important matters with your family members. Break that habit to get better sleep.Don’t go to bed too earlyYour body usually lets you sleep only the number of hours it needs. You should decide how many hours you must sleep in order not to experience daytime sleepiness.Take a warm shower before your bedtimeA twentyminute warm shower at a temperature of about 45 –50 not only is a great relax at day’s end, but also raises your body temperature by several degrees. The ing drop in temperature of your body will naturally make you feel sleepy.80. If you want to build up your body clocks, you should ________. A. set a certain bedtime and rising time B. go to bed neither too early nor too late C. keep the bedroom for sleeping only D. take a warm shower before sleeping81. Why should you avoid exciting activities just before sleeping? A. Because they will get your thoughts running B. Because you have to make tomorrow’s paln C. Because you should read an exciting story D. Because you will have to turn off the light.82. Your bedroom should be kept for ________ only. A. talking B. eating C. reading D. sleeping83. According to the passage, _________ will make you feel sleepy. A. taking a cold shower B. your body temperature dropping C. your daily experience D. raising your bod