请教LSAT16-III-3，8，18，23

joywzy

3. Organization president: The stationery and envelopes used in all of the mailings from our national headquarters are made from recycled paper, and we never put anything but letters in the envelopes. When the envelopes have windows are also made from recycled material. Therefore the envelopes and thus these mailings, are completely recyclable.

Which one of the following is an assumption on which the organization president's argument depends?

(A) All the paper used by the organization for purposes other than mailings is recycled.

(B) The mailing from the organization's national headquarters always use envelopes that have windows.

(C) The envelope windows made from recycled material are recyclable.

(D) The envelopes and stationery used in the organization's mailings are always recycled.

(E) The organization sends mailings only from its national headquarters
答案：C，我选D，我觉得D比C更好，C只讲envelop windows ，D讲:envelops and stationery used in mailing, 结论：the envelopes and thus these mailings, are completely recyclable. 所以D更好。
8. Delta green ground beetles sometimes remain motionless for hours at a stretch, although they are more active in wet years than in dry years. In 1989 an observer sported ten delta green ground beetles in nine hours; in 1985 the same observer at the same location had counted 38 in about two hours. This difference probably does not reflect a drop in the population of these rare beetles over this period, however, because 1985 was a wet year and 1989 was relatively dry.

Which one of the following, if true, most strongly supports the conclusion drawn above?

(A) Because of their excellent camouflage, delta green ground beetles are almost impossible to see if they are not moving.

(B) The only habitat of delta green ground beetles is around pools formed by the collection of winter rains in low-lying areas.

(C) Della green ground beetles move about very little to get food; most of their moving from one place to another is related 10 their reproductive behavior.

(D) Della green ground beetles are so rare that, although the first specimen was found in 1878, a second was not found until 1974.

(E) No predator relies on the delta green ground beetle for a major portion of its food supply.

答案：A，我觉得没有一个选项支持啊？

18. In experiments in which certain kinds of bacteria were placed in a generous supply of nutrients, the populations of bacteria grew rapidly, and genetic mutations occurred at random in the populations. These experiments show that all genetic mutation is random.

Which one of the following, if true, enables the conclusion to be properly drawn?

(A) Either all genetic mutations are random or none are random.

(B) The bacteria tested in the experiments were of extremely common forms.

(C) If all genetic mutations in bacteria are random, then all genetic mutations in every other life form arc random also.

(D) The kind of environment in which genetic mutation takes place has no effect on the way genetic mutation occurs.

(E) The nutrients used were the same as those that nourish the bacteria in nature.
答案： A，我选C
结论是all genetic mutation is random. 论据：genetic mutations occurred at random in the bateria,C不是把论据和论点bridge吗？

23. Asbestos, an almost indestructible mineral once installed as building insulation, poses no health risk unless the asbestos is disturbed and asbestos fibers are released into the environment. Since removing asbestos from buildings disturbs it, thereby releasing asbestos fibers, the government should not require removal of all asbestos insulation.

Which one of the following, if true, most strengthens the argument?

(A) Asbestos poses far less risk to health than does smoking, drug and alcohol abuse, improper diet or lack of exercise.

(B) Asbestos can post a health threat to workers who remove it without wearing required protective gear.

(C) Some kinds of asbestos, when disturbed, pose greater health risks than do other kinds.

(D) Asbestos is inevitably disturbed by building renovations or building demolition.
(E) Much of the time, removed asbestos is buried in landfills and forgotten with no guarantee that it will not be disturbed again.

答案：E，我选B，提干讲：removal of Asbestos will pose risk .B选项就是这个意思啊。为什么答案会是E？

谢谢！

StephanieYun

我来试试吧
第3题， 答案应该是C，我想这没有疑问。 题目的key其实在两个英文单词之间的理解和偷换概念。 就是 recyclable 和 recycled, 前者是可循环的， 后者是已被循环的。 注意哦。 d 中说的是， (D) The envelopes and stationery used in the organization's mailings are always recycled，信封和邮戳邮票都被经常循环使用。c说的是(C) The envelope windows made from recycled material are recyclable. 制作信封窗口的是recycled material 已被循环材料， 问题来了， 已被循环材料是否可以被循环呢？  尽管已被循环一次， 可否再被循环呢？ 所以，题目其实是偷换了recyclable 和 recycled 的概念， 所以应该选C. 而D只是说目前信封和用戳邮票经常被循环，而没有说明envelope windows made by recycled material 是否可以recyclable

第8题， 可爱的小蜜蜂题。 题目问如何支持结论。 In 1989 an observer sported ten delta green ground beetles in nine hours; in 1985 the same observer at the same location had counted 38 in about two hours. This difference probably does not reflect a drop in the population of these rare beetles over this period, however, because 1985 was a wet year and 1989 was relatively dry. A选项说小蜜蜂不动的时候难以被发现， 因为它有很好的伪装。 所以就支持了结论，不是因为小蜜蜂数量减少了 ，而是因为1985年是较为湿润的年份，而1989年则较为干燥，所以小蜜蜂活动减弱，能够被发现的就少了，所以限定时间内计数就比湿润年份的要少了。

第18题  基因突变题   题目结论是通过一个细菌培养试验， 其中发生了随机基因突变，所以所有细菌的基因突变都是随机的。 提问assumption是什么。 A选像说基因突变要么全部是随机的要么就都不是随机的。 所以就是assumption了。 C选像说(C) If all genetic mutations in bacteria are random, then all genetic mutations in every other life form arc random also. 如果所有细菌基因突变都是随机的，那么其他所有生命形式的基因突变都是随机的。这里有问题。 题目结论是所有基因突变都是随机的。这正是要寻求选项支持的。 但C却是基于这个需要支持的结论作了一个推论，却没有对结论本身作支持。

第23题   石棉材料损害题   B说(B) Asbestos can post a health threat to workers who remove it without wearing required protective gear. 如果工人不带防护器具就去移动石棉会遭受身体健康损害。 题目结论是政府不应该要求移去石棉。 所以B 不能支持结论------工人工作时戴不戴防护器具和是否因此受伤并不能成为政府是否应该要求移去石棉的理据； E说(E) Much of the time, removed asbestos is buried in landfills and forgotten with no guarantee that it will not be disturbed again. 被移去的石棉材料会被弃置在填埋区，不能保证是否会在以后再被disturbed， 而题目已经说了，石棉disturbed就会对人体造成伤害。 所以就支持了结论------the government should not require removal of all asbestos insulation. 政府不应该要求移去石棉材料。

哦，一口气打了那么多， 手软软的了  ， 不知道说的怎样， 愚见
多交流哦

祝生活快乐

回家过年

3. 类比论证. hidden premise 有本质联系,相关相通. 提干中有隐蔽的差异或跳跃:recycled material与recyclable D假设题答案要求必要性(但不是说满足这些必要条件就一定正确), C与D的区别:C虽然没有all这样的词,但是也没有some, many, always这样的模棱两可的词,其实就是有ALL(但是满足C这个必要条件并不能肯定前面的结论(特点),可是D虽然比C更全面了一点,但是always的出现使必要性大打折扣.

18. 同意, 提干与题目是两个不同的对象. 题干certain kinds of bacteria =====>all genetic mutation
题目:all genetic mutations in bacteria ======>in every other life .

joywzy

StephanieYun你详细的解答让我非常感动！！说得非常好非常到位！！！

23， 我又把结论看歪了，18， 我漏掉了other life.已经屡次有这种错误了。真是糟糕！！

3， 18，23完全赞成你们的意见！！我已经理解了。

可第8题是怎么支持结论的，还是有点糊涂，能否再讲讲。

非常感谢！！