图1所示数控车床的主传动系统采用的是（）的变速方式，可以避免齿轮传动引起的振动与噪声。图1带传动联轴器同轴联接变速齿轮内装式电主轴

>> 国家开放大学 / 数控机床

国家开放大学 / 数控机床

图1所示数控车床的主传动系统采用的是（）的变速方式，可以避免齿轮传动引起的振动与噪声。

图1

带传动

联轴器同轴联接

变速齿轮

内装式电主轴

积分

数控机床

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1[阅读题] Passage 1 The long summer holidays are finally over and some parents are pleased. “We worry more about their safety in the holidays,” explains one mother from North London. If teenagers are not wandering around on public transport in a big and potentially dangerous city, they are chatting to strangers in an internet chat room! Well, that’s an extreme picture of the UK today, but many parents are worried about how much freedom they can give their children during the holidays and at weekends. Weekends are not the only time to worry! Newspaper are full of stories about too many school kids going to school by car because their parents do not want them to travel alone on a bus or train. This summer there were more frightening stories of teenagers disappearing with questionable friends that they met on the net. All the Media stories help increase parents fears, but is the UK really so dangerous? Many young people feel that life for their parents was easier. In the 1960s young people played in the streets more and traveled around town without their parents. “At least our parents can keep tabs on us,” says 16-year-old Julia. “So many people have mobile phones now and their parents ring to find out where they are. I use my mobile to get Dad to come to the station when I arrive late.” Mobiles are not just expensive toys; they help keep young people safe. Most significantly, they help keep young people safe. Most significantly, they make parents feel better. Only one problem is, though, that some young people have been attacked by thieves who want to steal their mobile phones. Young people like going out with friends, but they now need to learn how to get home safely. Five million young people in the UK between the ages of 9 to 16 use chat rooms to make friends, but they, too, need to be careful and never give their personal details to a stranger. Young people today have more opportunities to meet new people and go out at night more than their parents ever did. Now school, television programs and newspapers must help teenagers to enjoy their freedom and to be responsible for their own safety. 6. Some parents are upset about the summer holidays mainly because their children ______. A. wander around on bus in the city B. chat to strangers in Internet chat rooms C. make questionable friends on the net D. are taken little care of by teachers 7. For the sake of the safety, many parents send their kids to school ________. A. by car B. by bus C. by train D. by public transport 8. Most significantly, mobile phones _______. A. enable parents keep a close watch on their kids B. help keep teenagers safe C. make parents feel less worried D. protect teenagers from being attacked 9. Teenagers should never give any strangers ______. A. their mobile phone numbers B. their family address C. their personal information D. their parents’ names 10. This passage is mainly about ________. A. freedom for teenagers in summer holidays B. safety for teenagers in summer holidays C. activities for teenagers in summer holidays D. troubles for teenagers in summer holidays DACCB Passage 2 I began teaching at the James School twenty-two years ago when I was twenty -six. In those days the place was very different. But time changes, and of course education theory changes, too. Methods and materials change. Even the classroom looks different. Twenty years ago, our classroom was a lot less pleasant. Very old-fashioned. We had fewer window, for example. There were five rows of desks, six desks in a row. Since everything was nailed to the floor, a student sat in the same place all day long. Oh, we had to be very strict. Now students move all over the room. They go to different areas for different subjects, and they write at these movable desks. 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A. the students are more mobile and attentive B. the teachers are more strict C. the teachers are less strict D. the students are less attentive and restless 3. The main idea of the third paragraph is about . A. the characteristic of the modified open classroom system B. the characteristic of the work contract C. the freedom of the students D. the generosity of the teachers 4. In a modified open classroom system, . A. the student needn’t do any home work B. the student can get more freedom in their study C. the subject that the student should learn is decided by the teacher D. there is not any discipline that the student should obey 5. According to the author, the educational system today is . A. more strict and attentive B. more pleasant and efficient C. is similar to the educational system twenty years age D. is satisfied by every teacher and student CAABB Passage3 A few years ago I was shopping with a friend and his 12-year-old daughter in downtown San Francisco. A street musician, whom my friend happened to know from his own musician days, was playing the saxophone(萨克斯管) on a street corner. His name was Clifford, and he had attracted a large crowd with his performance. After he finished, my friend introduced him to me and his daughter. Clifford asked her if she played any instrument. When she replied that she was taking trumpet(小号) lessons and played in her junior high school band, he said, "That's fine, little lady. Learn your instrument well and you can play anything. " Somehow these simple yet wise words struck me as appropriate not only for a trumpet player but also for a reader. If you learn to read well, you can read anything you want---not just newspapers and magazines, but more difficult material like philosophy, file criticism, military history---whatever interests you as your confidence grows. You would not be limited in any way. If you have the vocabulary---or at least a good dictionary near at hand---you can pick up a book, concentrate on it, and make sense of the author's words. In the United States, reading instruction often ends at elementary school, so students sometimes have difficulty as they progress through school. They must take their assignments armed only with their elementary school reading skills. The result, too often, is frustration and loss of confidence. And the assigned reading in your college courses will be even greater than they were in high school. Developing Reading Skills is designed to accomplish several tasks: to show you the skills that will enable you to read with greater comprehension, to help you cope with reading assignments with confidence, and to teach you to become an active reader. 26. The author develops his point by starting with ______. A. an example B. an incident C. a statement D. a contrast 27. Which of the following statements is implied in Paragraph 1? A. Clifford was good at playing the saxophone. B. The author's friend was once a street musician. C. The 12-year-old girl played the trumpet very poorly. D. Clifford was a good music teacher. 28. "Struck … as appropriate" in Line 1, Paragraph 2 most probably means ______. A. seemed to be appropriate B. proved to be appropriate C. happened to be appropriate D. found to be appropriate 29. With good reading skills, you can ______. A. understand anything you read without difficulty B. work out the author's meaning if only you concentrate on the book C. understand what you read with the help of a good dictionary D. concentrate on whatever you read 30. It can be inferred from the last paragraph that Developing Reading skills ______. A. is directed to elementary school students B. centers around vocabulary building skills C. offers elementary reading skills D. aims at helping students read better AAAAD英语语音

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