我总结的七月换题库后JJ 7/16 - 8/16, 已停止更新

qincong83

以下是引用newcder在2007-7-19 13:14:00的发言：
43题有问题：
 DS:三个数的数学平均数是否等于中间数？
(1)最大数和最小数的和是range的2倍

 (2)三个数的和是其中一个数的3倍

设三个数为x, x+m, x+n, n>m

根据1
x+x+n = 2n => x=n/2
(x+x+m+x+n)/3 = x+(m+n)/3=n/2+(m+n)/3  != n/2+m

应该选D啊，NN有高见吗？

===============================================
sorry,刚才没有看清楚,有一点补充
条件1成立 =〉n/2+(m+n)/3  = n/2+m =〉n=2m
所以(x+x+m+x+n)/3 =(3x+3m)/3 = x+m
答案选D

看这样做是不是快一点：

let A, B and C , A<B<C ;  ask (A+B+C)/3=B ?

1) A+C=2*(C-A)  so C=A    => the max number equals to the mix number, so A=B=C ; sufficient;

2) A+B+C=3A or 3B or 3C  => whatever which answer can infer A=B=C ; sufficient;

so the answer is D

liningsh

祝你LG得800！！！！！！！

shopgirl

以下是引用newcder在2007-7-18 16:57:00的发言：
LG下个月考，我负责帮他整理换题库后的JJ，所有整理的JJ都放在word文档里，大家可以参考。以后每天会更新，直到八月三号^_^

Good Luck!

Great

wingkim

以下是引用小GM在2007-7-19 13:53:00的发言：

请问一般情况下阅读的机井在实考中能中几篇的呀? 盼好心人回复下

曾经有人碰到四篇，我希望能碰上一、二篇。

已经发现7月出现超过5篇gwd

wingkim

以下是引用newcder在2007-7-19 13:14:00的发言：
43题有问题：
 DS:三个数的数学平均数是否等于中间数？
(1)最大数和最小数的和是range的2倍

 (2)三个数的和是其中一个数的3倍

设三个数为x, x+m, x+n, n>m

根据1
x+x+n = 2n => x=n/2
(x+x+m+x+n)/3 = x+(m+n)/3=n/2+(m+n)/3  != n/2+m

应该选D啊，NN有高见吗？

===============================================
sorry,刚才没有看清楚,有一点补充
条件1成立 =〉n/2+(m+n)/3  = n/2+m =〉n=2m
所以(x+x+m+x+n)/3 =(3x+3m)/3 = x+m
答案选D

看这样做是不是快一点：

let A, B and C , A<B<C ;  ask (A+B+C)/3=B ?

1) A+C=2*(C-A)  so C=A    => the max number equals to the mix number, so A=B=C ; sufficient;   似乎推出C=3A

2) A+B+C=3A or 3B or 3C  => whatever which answer can infer A=B=C ; sufficient;

so the answer is D

我的理解：1) A+C=2*(C-A)推出C=3A；

因A<B<C，所以2) A+B+C>5A不等于3A；A+B+C<3C；所以只有A+B+C＝3B－－>B=2A，

所以平均数为中值，答案为C

iloveit508

 如下几题有疑问

"43    DS:三个数的数学平均数是否等于中间数？

(1)最大数和最小数的和是range的2倍

(2)三个数的和是其中一个数的3倍

       答案为B

       更正答案D

50    种东西，15%得了真菌并死了。有40%的得了真菌的没有死。问得了真菌的占总数的多少。

答案60%*X=15%=25%

70    长40的square, 卷成圆筒, 问圆筒 volume?

       答案1600

90   x>0y<0, z<0, 问([x]+[y]+[z])^2的展开式？

       答案x^2+y^2+z^2+2xy+2xz+2yz

 "

43 应该选B,  (1 )只能说明最大的是最小的三倍,

     (2)能说明三个的和就是中间数的三倍,平均数等于中间数

50 

没看懂题目, 为啥不是15%+40%=55%?

70  1600=40*40是侧面积啊, volume体积应该是16000/pi

90  这个还是没看懂题目,[X] [y] [z]是x,y,z的绝对值吗? 如果是的话答案不对啊

wingkim

LZ RC里面的补充

13，月球的形成
一.分裂说。这是最早解释月球起源的一种假设。早在1898年，著名生物学家达尔文的儿子乔治·达尔文就在《太阳系中的潮汐和类似效应》一文中指出，月球本来是地球的一部分，后来由于地球转速太快，把地球上一部分物质抛了出去，这些物质脱离地球后形成了月球，而遗留在地球上的大坑，就是现在的太平洋。这一观点很快就收到了一些人的反对。他们认为，以地球的自转速度是无法将那样大的一块东西抛出去的。再说，如果月球是地球抛出去的，那麽二者的物质成分就应该是一致的。可是通过对“阿波罗12号”飞船从月球上带回来的岩石样本进行化验分析，发现二者相差非常远。

二.俘获说。这种假设认为，月球本来只是太阳系中的一颗小行星，有一次，因为运行到地球附近，被地球的引力所俘获，从此再也没有离开过地球。还有一种接近俘获说的观点认为，地球不断把进入自己轨道的物质吸积到一起，久而久之，吸积的东西越来越多，最终形成了月球。但也有人指出，向月球这样大的星球，地球恐怕没有那麽大的力量能将它俘获。

三.同源说。这一假设认为，地球和月球都是太阳系中浮动的星云nebula，经过旋转和吸积，同时形成星体celestial body (e.g. planet, satellite, etc.)。在吸积过程中，地球比月球相应要快一点，成为“哥哥”。这一假设也受到了客观存在的挑战。通过对“阿波罗12号”飞船从月球上带回来的岩石样本进行化验分析，人们发现月球要比地球古老得多。有人认为，月球年龄至少应在70亿年左右。

四.大碰撞说。这是近年来关于月球成因的新假设。1986年3月20日，在休士顿约翰逊空间中心召开的月亮和行星讨论会上，美国洛斯阿拉莫斯国家实验室的本兹、斯莱特里和哈佛大学史密斯天体物理中心的卡梅伦共同提出了大碰撞假设。这一假设认为，太阳系演化早期，在星际空间曾形成大量的“星子”planetesimal，星子通过互相碰撞、吸积而长大。星子合并形成一个原始地球，同时也形成了一个相当于地球质量0.14倍的天体。这两个天体在各自演化过程中，分别形成了以铁为主的金属核和由硅酸盐silicate构成的幔和壳。由于这两个天体相距不远，因此相遇的机会就很大。一次偶然的机会，那个小的天体以每秒5千米左右的速度撞向地球。剧烈的碰撞不仅改变了地球的运动状态，使地轴倾斜，而且还使那个小的天体被撞击破裂，硅酸盐壳和幔受热蒸发，膨胀的气体以及大的速度携带大量粉碎了的尘埃飞离地球。这些飞离地球的物质，主要有碰撞体的幔组成，也有少部分地球上的物质，比例大致为0.85:0.15。在撞击体破裂时与幔分离的金属核，因受膨胀飞离的气体所阻而减速，大约在4小时内被吸积到地球上。飞离地球的气体和尘埃，并没有完全脱离地球的引力控制，他们通过相互吸积而结合起来，形成全部熔融的月球，或者是先形成几个分离的小月球，在逐渐吸积形成一个部分熔融meltdown的大月球。

22.      还有个火山是地壳里面热石头被压到地面形成的 是否下面这篇？

1.        GWD-7-Q22 to Q25形成火山的两个机理

     Earth’s surface consists of rigid

       plates that are constantly shifting and

       jostling one another.  Plate movements

Line       are the surface expressions of motions

  (5)      in the mantle—the thick shell of rock

that lies between Earth’s crust and its

metallic core.  Although the hot rock of

the mantle is a solid, under the tre-

mendous pressure of the crust and

 (10)      overlying rock of the mantle, it flows like

a viscous liquid.  The mantle’s motions,

analogous to those in a pot of boiling

water, cool the mantle by carrying hot

material to the surface and returning

 (15)      cooler material to the depths.  When

the edge of one plate bends under

another and its cooler material is con-

sumed in the mantle, volcanic activity

occurs as molten lava rises from the

 (20)      downgoing plate and erupts through the

       overlying one.

             Most volcanoes occur at plate               （数量程度词）

boundaries.  However, certain “mis-            （转折，另一种成因）

placed” volcanoes far from plate

 (25)      edges result from a second, indepen-

dent mechanism that cools the deep

interior of Earth.  Because of its prox-

imity to Earth’s core, the rock at the

base of the mantle is much hotter than

 (30)      rock in the upper mantle.  The hotter the

mantle rock is, the less it resists flow-

ing.  Reservoirs of this hot rock collect

       in the base of the mantle.  When a

reservoir is sufficiently large, a sphere

 (35)
                    of this hot rock forces its way up

through the upper mantle to Earth’s

surface, creating a broad bulge in the

topography.  The “mantle plume” thus     （产生结果）

      formed, once established, continues to

 (40)     channel hot material from the mantle

base until the reservoir is emptied.

The surface mark of an established

plume is a hot spot—an isolated

region of volcanoes and uplifted terrain

 (45)      located far from the edge of a surface

plate.  Because the source of a hot        （强因果关系）

spot remains fixed while a surface

plate moves over it, over a long period

of time an active plume creates a chain

 (50)      of volcanoes or volcanic islands, a

track marking the position of the plume

relative to the moving plate.  The natural

history of the Hawaiian island chain

clearly shows the movement of the

Pacific plate over a fixed plume.

wingkim

还是这篇，感觉有点像后面这篇

1.        GWD-30-Q11-Q13 最老的火山岩石和发现它的科学意义

     First identified in 1969, komatiites   （时间标志）

       are Earth’s oldest known volcanic

       rocks and contain three times as much

Line       magnesium as do most volcanic rocks.

  (5)      This chemical composition suggests   （显示推测）

that komatiites formed from the hottest

lava known ever to have erupted:  a

high concentration of magnesium       （对比）

changes the physical properties of

 (10)      lava so that unusually high tempera-

tures would be required for the lava

to exist as a liquid.

      Komatiites’ discovery was surpris-

ing in light of then-current geological

 (15)      theories about magmas, molten rock

that forms in the Earth’s mantle (the

layer beneath the crust) and composes

volcanic lava eruptions.  Prior to 1960,

geologists Bowen and Hess disagreed

 (20)      over whether or not the very high tem- （选择性词组）

       peratures needed to produce magmas

       rich in magnesium could have existed

on Earth.  Hess suggested that
    the     （H的观点）

presence of water, probably released

 (25)      from minerals decomposing in the

Earth’s mantle, might have meant that

a high-magnesium magma could have

existed at a lower temperature.  But

Bowen showed experimentally that the  （B的相反观点）

 (30)      high temperatures were indeed nec-

essary.  By 1960, it was generally     （普遍性）

accepted that volcanic rocks with such

       high levels of magnesium could not

exist, and thus the discovery of koma-

 (35)
       tiites changed geologists’ assumptions

about the characteristics of the Earth’s

mantle around the time of the formation

of komatiites, between 2.5 and 4 billion

      years ago.

--------------------------------------------------------------------------------

逻辑简图：现象解释型

P1：portray a discovery and the suggestion of it；First identified in 1969, suggested that high concentration… high temperatures

P2：discovery of K物质lead to a new consideration of the formation of K；whether or not，H suggest that…, But B showed that…，By 1960, …generally…,and thus

--------------------------------------------------------------------------------

 

 

Q11:

Which of the following most accurately describes the organization of the passage?

             

1. Two divergent views of a scientific phenomenon are reconciled.
2. A phenomenon is described and its scientific significance is discussed.

3. The discovery of a scientific phenomenon is traced and its implications for further research are suggested.
4. A long-standing scientific theory is examined and recently discovered evidence is shown to support it.
5. The ways in which a particular geological phenomenon is exceptional are detailed and classified.

 

 

By 1960, it was generally     （普遍性）

accepted that volcanic rocks with such

       high levels of magnesium could not

exist, and thus the discovery of koma-

 (35)
       tiites changed geologists’ assumptions

about the characteristics of the Earth’s

mantle around the time of the formation

of komatiites, between 2.5 and 4 billion

      years ago.

---------------------------------------------------------------

Q12:

Information in the passage suggests which of the following concerning the Earth’s mantle 2.5 to 4 billion years ago?

             

1. It contained magmas that were more significantly affected by the decomposition of minerals than are current-day magmas.
2. It contained a lower proportion of water that it contains today.
3. Its characteristics were accurately described by both Bowen and Hess.
4. Its temperature was sufficiently high
         to produce
         magmas with high magnesium content.

5. Its total magnesium content then was roughly equivalent to its magnesium content today.

 Prior to 1960,

geologists Bowen and Hess disagreed

 (20)      over whether or not the very high tem-
   （选择性词组）

       peratures
    needed to
    produce magmas

       rich in magnesium could have existed

on Earth.

By 1960, it was generally     （普遍性）

accepted that volcanic rocks with such

       high levels of magnesium could not

exist, and thus the discovery of koma-

 (35)
       tiites changed geologists’ assumptions

about the characteristics of the Earth’s

mantle around the time of the formation

of komatiites, between 2.5 and 4 billion

      years ago.

-----------------------------------------------------------------

Q13:

Which of the following most accurately states the main point of the passage?

             

1. Komatiites provide information about rates of volcanic eruption between 2.5 and 4 billion years ago.
2. Komatiites provide information about how the physical properties of lava in the Earth’s past compare with those of current-day lava.
3. Komatiites provide evidence that undermines Bowen’s experimental conclusions regarding the temperatures at which lava exists as a liquid.
4. Komatiites provide evidence that has changed
         geologists’ ideas about the characteristics of the Earth’s mantle
        between 2.5 and 4 billion years ago.

5. Komatiites provide evidence that water in the Earth’s mantle may have reduced the temperature required for lava to exist as a liquid.

 

 

By 1960, it was generally     （普遍性）

accepted that volcanic rocks with such

       high levels of magnesium could not

exist, and thus the discovery of koma-

 (35)
       tiites changed
    geologists’ assumptions

about the characteristics of the Earth’s

mantle around the time of the formation

of komatiites, between 2.5 and 4 billion

      years ago.

希望LZ确认补充到里面去

[此贴子已经被作者于2007-7-19 23:42:28编辑过]

iloveit508

还有这道SC jj, 到底是选A还是B?

1.         SC：Warm air can hold more water than.......(选项里面没有cool air的选择，只有A，B那两个，以及后面几个我觉得很明显不对的选项)
A) cool air can
B) cool air can do
C).....
D).....
E)....

newcder

Thanks to wingkim & iloveit508, 我做了一些纠正和补充

43题是我糊涂了,还是用mixtec的公式:条件1成立 =〉n/2+(m+n)/3  .这里不能确定 n/2+(m+n)/3是否等于x+m(也就是n/2+m) ,因为m＆n的关系不清楚.答案应该是B