题目

去年某果园随机从甲、乙、丙、丁四个品种的葡萄树中各采摘了10棵，每棵产量的平均数（单位：千克）及方差（单位：千克）如下表所示： 甲乙丙丁242423202.11.921.9 今年准备从四个品种中选出一种产量既高又稳定的葡萄树进行种植，应选的品种是（）A. 甲 B. 乙 C. 丙 D. 丁 答案：【答案】B【解析】先比较平均数得到甲组和乙组产量较好，然后比较方差得到乙组的状态稳定．因为甲组、乙组的平均数丙组比丁组大，而乙组的方差比甲组的小，所以乙组的产量比较稳定，所以乙组的产量既高又稳定，故选B．Like fine food, good writing is something we approach with pleasure and enjoy from the first taste to the last. And good writers, like good cooks, do not suddenly appear full-blown. Quite the opposite, just as the cook has to undergo a particular training, mastering the skills of his trade, the writer must sit at his desk and devote long hours to achieving a style in his writing, whatever its purpose is—schoolwork, matters of business, or purely social communication. You may be sure that the more painstaking the effort, the more effective the writing, and the more rewarding. There are still some faraway places in the world where you might find a public scribe to do your business or social writing for you, for money. There are a few managers who are lucky enough to have the service of that rare kind of secretary who can take care of all sorts of letter writing with no more than a quick note to work from. But for most of us, if there is any writing to be done, we have to do it ourselves. We have to write school papers, business papers or home papers. We are constantly called on to put words to papers. It would be difficult to count the number of such words, messages, letters, and reports put into mails or delivered by hand, but the daily figures must be extremely large. What is more, everyone who writes expects, or at least hopes whatever he writes will be read,    from first word to last, not just thrown into some “letters-to-be-read” files or into a wastepaper basket. This is the reason we bend our efforts toward learning and practicing the skills of interesting, effective writing.1.In this passage, good writing is compared to fine food because _______. A.both are enjoyableB.both are hard to learnC.both are necessary to lifeD.both take a long time to prepare2.according to the passage, which of the following statements is true?A.Writing skills are less important than experience.B.A good writer should have his own way of writing.C.A good writer should learn to write all kinds of articles.D.The more efforts one makes, the more money one can earn.3.The author thinks that the most important reason for us to practice writing skills is _______. A.to earn our livingB.to attract others to readC.to do daily reports easilyD.to become good secretaries4.The purpose of the author in writing this passage is to _______. A.comment and blameB.introduce and describeC.explain and persuadeD.interest and inform