指点：og-175,费费宝典114

summerlotus

Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae.

Which of the following conclusions can properly be drawn from the information above?

(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp’s egg-laying behavior.

(B) Host insects lack any effective defenses against the form of predation practiced by parasitic wasps.

(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.

(D) Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs

(E) Parasitic wasps use visual clues to calculate the size of a host egg.  答案是,A,OG解释也看了，不明白啊。人家的蛋的大小可以由它来决定？

The number of North American children who are obese-that is, who have more body fat than do 85 percent of North American children their age---is steadily increasing, according to four major studies conducted over the past 15 years.

If the finding reported above is correct, it can be properly concluded that

(A) when four majors studies all produce similar results, those studies must be accurate

(B) North American children have been progressively less physically active over the past 15 years

(C) the number of North American children who are not obese increased over the past 15 years

(D) over the past 15 years, the number of North American children who are underweight has declined

(E) the incidence of obesity in North American children tends to increase as the children grow older

答案是,C我怎么不明白呢？解释一下

番茄炒蛋

第一题的size是指数量的size而不是指大小，你应该是这里理解错了


第二题胖子总是占15％的，那这部分人数增加了而百分比又没有变化，所以当然是总人数要增加咯


呵呵，你再瞧瞧


    

amo

不好意思，我觉得size应该是指的大小而不是数量，因为文中指数量用的都是number，指大小都是用的size，不会在选项中就去指数量吧？文中提到“suitable size of host egg”也就是说焦点词应该是关于“size”的，且文中的hidden premise就是size有个适当的范围，否则那生物怎么去确定产蛋的数量呢？


不过我觉得这有点像假设题而不是归纳题，应为A显然是一个使结论成立的必要条件

mildsevens

个人认为，size还是应该表示大小，determined可以理解成推断，这样就顺畅多了。

dadada007

OG175不明白这个题目，已经第二次过OG了，还是搞不懂。The size of the smallest host egg ===无论这个SIZE是指数量还是大小，也无法确定 smallest的啊。为什么C不对呢？真知来自于实践，(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species. ===题目给出的信息，如果Parasitic wasp失败多了，那总有一次是它满意的啊，那么下次就根据这个去做了，这不是合乎逻辑么？

请教NN啊，

dadada007

ding dingpls help

dadada007

继续顶............................

hoover

(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.中的learn from和how many用的不妥。]

A）的意思已经很明确了。wasps能够根据host egg size来产下适合该size的俄eggs。归纳题。

snowjing

以下是引用hoover在2005-4-18 20:19:00的发言：

(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species.中的learn from和how many用的不妥。]

A）的意思已经很明确了。wasps能够根据host egg size来产下适合该size的俄eggs。归纳题。

A的意思并不是"wasps能够根据host egg size来产下适合该size的俄eggs", 而是"wasp的下蛋行为决定了他所需要的寄主蛋的大小的最小值".

试着解释一下：

1) 这个最小值只是为了说明wasp的下蛋行为是出于本能的，为了避免蛋或卵的死亡(下多下少都要死)，他们必须做到下蛋数目刚好适合宿主蛋的大小。当然，这里的"the smallest"也可以省略。不影响中心思想的表达(OG也是假设comparing two host eggs...来论证)。

2) 有一点必须指出，the size of host egg that a wasp could theorectically parasitize can be determined from the wasp's egg-laying behavior. 其中that定语从句的修饰说明了host egg是指wasp可以下蛋的host eggs, 也进一步说明了host eggs 是客观已经存在的，所以不存在“host egg是由wasp's egg-laying behavior产生”的意思，更不可能说host egg的size也由别人来决定了。

一家之言，请大家指正。

[此贴子已经被作者于2005-7-27 1:40:50编辑过]

Andrea625

以下是引用snowjing在2005-7-27 1:26:00的发言：

A的意思并不是"wasps能够根据host egg size来产下适合该size的俄eggs",{ 请问哪个是原因，是先决条件？} 而是"wasp的下蛋行为决定了他所需要的寄主蛋的大小的最小值".{题目中隐含了很明显的先后是host egg的大小决定wasp下蛋的多少，而不可能是wasp下蛋多决定host egg大，下蛋少，决定host egg小。§§又看了几遍，明白你的意思了，看能不能这么理解：wasp下蛋的行为不是决定了，而是可以倒推出host egg的大小。如果你认为wasp想下多点蛋，所以要找一个大的host egg，那题目中没有说到wasp选择host egg的问题。想这个就想多了。}

试着解释一下：

1) 这个最小值只是为了说明wasp的下蛋行为是出于本能的{这个从题目中得不出来，wasp准确知道下蛋多少合适的能力的来源并不清楚，不能用来理解题目}，为了避免蛋或卵的死亡(下多下少都要死)，他们必须做到下蛋数目刚好适合宿主蛋的大小{就是碰到大的host egg就下多点蛋，碰到小的就下少点。如果碰到的这个host egg太小，只能下一个蛋，那这个host egg就是最小的了－－wasp知道再小就不能下了，我们也可以从wasp的下蛋的行为：下多点蛋、下少点蛋、下一个蛋、不下蛋知道最小的host egg的size}。       

当然，这里的"the smallest"也可以省略。不影响中心思想的表达(OG也是假设comparing two host eggs...来论证)。{？}

2) 有一点必须指出，the size of host egg that a wasp could theorectically parasitize can be determined from the wasp's egg-laying behavior. 其中that定语从句的修饰说明了host egg是指wasp可以下蛋的host eggs{指得是单数，没有s，是在讨论一个抽象的host egg},

也进一步说明了host eggs 是客观已经存在的，所以不存在“host egg是由wasp's egg-laying behavior产生”的意思{host eggs是客观存在的，但是wasp有的不下蛋，有的下一个蛋，有的下很多蛋，这区分开了这些客观存在的host eggs，并非是决定了host eggs}，更不可能说host egg的size也由别人来决定了.

determined不是决定的意思,而是（从理论上）（可以从哪些条件）推导出来的意思。是不是对determined的理解误导了你？

[此贴子已经被作者于2005-7-28 2:59:20编辑过]