标题: 请教LSAT－12－IV－15,19 [打印本页] 作者: joywzy 时间: 2003-6-14 14:47 标题: 请教LSAT－12－IV－15,19 15. A certain experimental fungicide causes no harm to garden plants, though only if it is diluted at least to ten parts water to one part fungicide. Moreover, this fungicide is known to be so effective against powdery mildew that it has the capacity to eliminate it completely from rose plants. Thus this fungicide, as long as it is sufficiently diluted, provides a means of eliminating powdery mildew from rose plants that involves no risk of harming the plants.
Which one of the following is an assumption on which the argument depends?
(A) There is not an alternative method, besides application of this fungicide. for eliminating powdery mildew from rose plants without harming the plants.
(B) When the fungicide is sufficiently diluted. it does not present any risk of harm to people, animals. or beneficial insects.
(C) Powdery mildew is the only fungal infection that affects rose plants.
(D) If a fungicide is to be effective against powdery mildew on rose plants, it must eliminate the powdery mildew completely.
(E) The effectiveness of the fungicide does not depend on its being more concentrated than one part in ten parts of water.
答案：E，虽然我猜对了答案，但不明白为什么E是假设。
19. The proposal to extend clinical trials, which are routinely used as systematic tests of pharmaceutical innovations, to new surgical procedures should not be implemented. The point is that surgical procedures differ in one important respect from medicinal drugs: a correctly prescribed drug depends for its effectiveness only on the drug's composition, whereas the effectiveness of even the most appropriate surgical procedure is transparently related to the skills of the surgeon who uses it.
The reasoning in the argument is flawed because the argument
(A) does not consider that new surgical procedures might be found to be intrinsically more harmful than the best treatment previously available
(B) ignores the possibility that the challenged proposal is deliberately crude in a way designed to elicit criticism to be used in relining the proposal
(C) assumes that a surgeon's skills remain unchanged throughout the surgeon's professional life
(D) describes a dissimilarity without citing any scientific evidence for the existence of that dissimilarity
(E) rejects a proposal presumably advanced in good faith without acknowledging any such good faith .
答案：A，我选了C，不明白A为何是错误
谢谢。作者: mindfree 时间: 2003-6-15 02:41
1. Premises: a. 10:1 no harm; b. effective in eliminating PM, no mention of concentration conclusion: no harm and effective at the same time. So assumtion is effective when 10:1.
If effective only 3:1, then it can not be harmless and effective.
2. A points out that the clinical trial is to identify the nature and possible risk involved in the procedure. C is not mentioned or implied.作者: joywzy 时间: 2003-6-15 19:53
mindfree,
Referring to T1, I have to admit that the key of CR is reading ability , the ability that can distinguish premise and conclusion.
T2, A points out the inherient risk that , I thought, it is irrevelant.
Could you please explain T 2 in detail?
Thank u very much.作者: albert 时间: 2003-6-16 03:55
let me try to explain T2
T2 argue that due to the dependce on skills of different surgeon, surgical procedure should not rely on surgical trial.
However, the arguer ignore the fact that an immature surgical procedure lack of the trial , as a rule, will be more harmful than a mature sugrical with full trial and efficiecy proof. That is the meaning of answer A作者: joywzy 时间: 2003-6-16 17:35
Thank u ,albert, i got it .