It seems like only yesterday that I was sitting where you are, just finishing my first year of medical school and wondering if I'd ever get a chance to use all my new knowledge on a real live patient! Well, I have good news for you! You don't have to wait until your third or fourth year of medical school to get some hands-on experience! The dean has invited me here to tell you about the university's rural opportunity program. If you enroll in this program, you can have the opportunity this summer, after your first year of medical school, to spend from four to six weeks observing and assisting a real physician like me in a small rural community. You won't have to compete with other students for time and attention, and you can see what life as a country doctor is really like. The program was designed to encourage medical students like yourselves to consider careers in rural communities that are still understaffed. It seems that medical students are afraid to go into rural family practice for two reasons. First, they don't know much about it. And second, specialists in the cities usually make more money. But, on the up-side, in rural practice, doctors can really get to know their patients and be respected members of the community. I participated in the program when it first started and spent six weeks in a small rural town. Let me tell you, it was really great! I got to work with real patients. I watched the birth of a child, assisted an accident victim, and had lots of really practical hands-on experience---all in one summer. And to my surprise, I found that country life has a lot to offer that city life doesn't---no pollution or traffic jams, for instance! My experience made me want to work where I'm needed and appreciated. I don't miss the city at all!

Good evening. My name is Pam Jones, and on behalf of the Modern Dance club, I’d like to welcome you to tonight's program. The club is pleased to present the TV version of The Catherine Wheel, Twyla Tharp's rock ballet. This video version of the ballet has been even more successful with audiences than the original theater production----it includes some animation, slow motion, and stop-action freezes that really help the audience understand the dance. The title of the piece refers to Saint Catherine, who died on a wheel in 307 A.D. Nowadays, a Catherine wheel is also a kind of firework----it looks something like a pinwheel. Anyway, the dance is certainly full of fireworks! You’ll see how Twyla Tharp explores one family's attempt to confront the violence in modern life. The central symbol of the work is a pineapple...but exactly what it represents has always created a lot of controversy. As you watch, see if you can figure it out. The music for this piece is full of the rhythmic energy of rock music. It was composed by David Byrne...of the rock band Talking Heads? And the lead dancer in this version was , who is perfectly suited to Tharp's adventurous choreography. Following the video, dance teacher Mary Parker will lead a discussion about the symbolism Ms. Tharp used. We hope you can stay for that. So, enjoy tonight's video...and thank you for your support.

生命的价值不依赖我们的所作所为，也不仰仗我们结交的人物，而是取决于我们本身！我们是独特的--永远不要忘记这一点。

Professor: , U5 |9 i5 |# L; v8 Y
$ Okay, today we’re going to discuss the four major types of drainage patterns. I trust you’ve already read the chapter so you’ll recall that a drainage pattern is the arrangement of channels that carry water in an area. And these patterns can be very distinctive since they’re determined by the climate, the topography, and the composition of the rock that underlies the formations. So, consequently, we can see that a drainage pattern is really a good visual summary of the characteristics of a particular region, both geologically and climactically. In other words, when we look at drainage patterns, we can draw conclusions about the structural formation and relief of the land as well as the climate.
6 J2 h4 j9 d1 K6 GNow all drainage systems are composed of an! u" B. G9 {8 W
interconnected# F! `# k, V# w" c/ N! Q; i5 `
network of streams, and, when we view them together, they form distinctive patterns. Although there are at least seven identifiable kinds of drainage patterns, for our purposes, we’re going to limit our study to the four major types. Probably the most familiar pattern is the dendritic drainage pattern.
- x0 t) ]. Q: k+ X) [$ This is a stream that looks like the branches of a tree. Here’s an example of a dendritic pattern. As you can see, it’s similar to many systems in nature. In addition to the structure of a tree, it also resembles the human circulation system. This is a very efficient drainage system because the overall length of any one branch is fairly short, and there are many branches, so that allows the water to flow quickly and efficiently from the source or sources.
9 x" }* i8 D+ b# X1 w$ Okay, let’s look at the next example. . b. C$ ^( A- u
$ This drainage pattern is referred to as a radial pattern. Notice how the streams flow from a central point. This is usually a high mountain, or a volcano. It kind of looks like the spokes that radiate out from the hub of a wheel. When we see a radial pattern, we know that the area has experienced uplift and that the direction of the drainage is down the slopes of a relatively isolated central point.
5 L1 k; D3 ~: R( O" J$ Going back to the dendritic for a moment. The pattern is determined by the direction of the slope of the land, but it, uh, the streams flow in more or less the same direction, and . . . so it’s unlike the radial that had multiple directions of flow from the highest point.
0 u% c# i: F2 {0 o3 D$ Now this pattern is very different from either the dendritic or the radial.   e+ u) i) Z- i+ I! S- L* M9 B" A0 Y
$ This is called a rectangular pattern, and I think you can see why. Just look at all of those right-angle
7 [6 Q) z% t( K( ~( j- E) ~/ \turns. The rectangle pattern is typical of a landscape that’s been formed by fractured joints and faults. And because this broken rock is eroded more easily than unbroken rock, stream beds are carved
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the jointed bedrock.
% M9 `7 S! {6 M0 F: _. T* x4 y% o! N$ Finally we have the trellis pattern. And here in this example, you can see quite clearly how the tributaries of an almost parallel structure drain into valleys and . . . and form the appearance of a garden trellis. This pattern forms in areas where there are alternating bands of variable resistance, and by that I mean that the bands of rock that are very strong and resistant to erosion
' i% X- \* X, {9 p. dalternate with bands of rock that are weak and easily eroded. This often happens when a horizontal plain folds and outcroppings appear. % ~: k  U8 J) S0 _. J
$ So, as I said, as a whole, these patterns are dictated by the structure and relief of the land.
0 _& c3 s0 @/ j* r$ The kinds of rocks on which the streams are developed, the structural pattern of the folds, uh, faults, and . . . uplift will usually determine a drainage system. However, I should also mention that drainage patterns can occasionally appear to be, well, out of sync with the landscape. And this can happen when a stream flows over older structures that have been uncovered by erosion or . . . or when a stream keeps its original drainage system when rocks are uplifted. So when that happens, the pattern appears to be contrary to the expected course of the stream. But I’m interested in% q- F$ Z! |  i- t
your understanding the basic drainage systems. So I don’t plan to trick you with test questions about exceptional patterns, but I expect you to know that exceptions to the patterns can occur when geological events# e& o8 g* i! p& g3 F
influence
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[ 本帖最后由 icenot 于 2008-4-9 23:53 编辑 ]

呃 楼上红色显示不出来…………

I'm glad you brought up the question of our investigations into the makeup of the Earth's interior. In fact---since this is the topic of your reading assignment for next time---let me spend these last few minutes of class talking about it. There were several important discoveries in the early part of this century that helped geologists develop a more accurate picture of the Earth's interior. The first key discovery had to do with seismic waves---remember they are the vibrations caused by earthquakes. Well, scientists found that they traveled thousands of miles through the Earth's interior. This finding enabled geologists to study the inner parts of the Earth. You see, these studies revealed that these vibrations were of two types: compression---or P---waves and shear---or S---waves. And researchers found that P waves travel through both liquids and solids, while S waves travel only through solid matter. In 1906 a British geologist discovered that P waves slowed down at a certain depth but kept traveling deeper. On the other hand, S waves either disappeared or were reflected back, so he concluded that depth marked the boundary between a solid mantle and a liquid core. Three years later another boundary was discovered---that between the mantle and the Earth's crust. There's still a lot to be learned about the Earth. For instance, geologists know that the core is hot. Evidence of this is the molten lava that flows out of volcanoes. But we're still not sure what the source of the heat is.

Today I want to talk about the Earth's last major climatic shift, at the end of the last ice age. But first, let’s back up a moment and review what we know about climatic change in general. First, we defined "climate" as consistent patterns of weather over significant periods of time. In general, changes in climate occur when the energy balance of the Earth is disturbed. Solar energy enters the Earth's atmosphere as light and is radiated by the Earth's surface as heat. Land, water, and ice each affect this energy exchange differently. The system is so complex that, to date, our best computer models are only crude approximations and are not sophisticated enough to test hypotheses about the causes of climatic change. Of course, that doesn't keep us from speculating. For instance, volcanic activity is one mechanism that might affect climatic change. When large volcanoes erupt, they disperse tons of particles into the upper atmosphere, where the particles then reflect light. Since less light is entering the system of energy exchange, the result would be a cooling of the Earth's surface. Of course, this is just one possible mechanism of global climate change. In all probability, a complete explanation would involve several different mechanisms operating at the same time.

I'd like to begin by thanking Dr. Kane for inviting me to be here today. Although I'm not a geologist, I have been collecting minerals for years. My collection is really diverse because I've traveled all over the world to find them. Today I've brought a few specimens for you to see. After I discuss each one, I'll pass it around so that you can look at it more closely. As you know, feldspars are the most abundant minerals and are divided into a number of types. These first samples are orthoclases. Notice that they vary in color from white to pink to red. This glassy one is found in volcanic rock---in fact, I found it in New Mexico on a collecting trip. This next sample that I'll pass around is a microcline mineral---also called Amazon stone. You can identify it by its bright green color. It's often used in jewelry and really is quite attractive. These final samples are all plagioclase feldspars. Many plagioclases are very rare, so I'm particularly proud of the variety in my collection. I've also brought a few slides of some large mineral samples, and if you'll turn out the light now, I'd like to show them to you.

第一篇  [, E* B# A2 e! S3 J# M$ x
Investigation
  {; _5 L2 D% l9 Q7 pmakeup
' X. o8 ^, k- ^( mgeologist" p! r$ m) R9 t: D) Z- g
interior) t* [2 E8 g1 v( ]
seismic
8 h  ~4 @, Y8 s4 w- {! D+ Qwave$ T) X. M. M5 y& g. U: S
vibration
, [- v; k1 N5 e) w2 ^0 Uearthquake3 Q" y* w" W7 [) L) w2 F
scientist8 c8 s( p- o) u; L; Y/ d4 N4 F; c. ]
inner
, [5 w& Y* ~& Y  k; jreveal% j* V* u; b7 u# d" o  j7 W' t" w
compression9 Q  J: Q# {& G9 K, V' r3 ~$ X
shear
7 p& s# ^2 ~3 V# Y& E& D/ X6 Zresearcher$ B$ Q5 q/ b! A, y* m0 y, I3 ^
liquid- w  R0 h6 h: W: `6 k
solid& Q, o6 V4 R9 k/ R" J! n
gas# b' H  x# T  q* ?! Y
matter
, q  a2 G2 s; o( H# G3 b$ Idiscover
1 R5 Z* W7 u+ F) d3 a  ndisappear( w5 d9 N8 l: z/ d
reflect
; c9 l8 v0 N+ u+ fconclude5 y* b" `( I" N% v, J
mantle
. A) I/ [, G! J0 t: s9 Ycore
0 f$ N  N+ y$ [, Pcrust
, m) U0 V7 [6 u- R" A; ]1 ilava' B+ a, h" h  G4 G& N% g
molten. q: w, M% ~, w  j4 {: B9 {
volcano5 q8 R* O; e5 E
source
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0 A3 v. G; _7 j4 b& C! e4 [第二篇! h5 M0 ]2 |7 i
Climatic shift4 f1 w  V0 E8 A' n
ice age0 i; a: v8 o1 Z* B. J) ^" \) G
climatic change3 U- }* B$ P( h5 N+ s
consistent' l7 s3 \. F3 x' q" M: U) l
pattern
- G5 g$ \6 T5 {9 W- H, h, asignificant# w9 p- j3 J7 w% Q  D7 ]
occur
1 R, x  h5 h6 _# J% F9 \' Genergy balance
8 P! d4 X% N5 Q% `disturb
( Q9 a8 l3 Q7 {+ G' ^enter) {2 N. W% F  ]: U3 t
solar energy* j% T  h5 A9 O9 W
atmosphere
- q: F& A* M- b2 }9 m2 lradiated
1 c. ]& m( I/ Zsurface
  ~  ~! k/ _% F- hexchange% O0 r& Y% _% f! b
system' M# H9 p% L8 ]8 a& \5 _# F8 O5 l
crude approximation. ]' |+ S$ Z1 k5 B6 Y( }1 M7 D' W
sophisticate
2 t7 n1 o  v4 U1 q& Whypotheses/hypothesis
, Z* l- Q' Z" C, w: @4 Jspeculate
( [- L7 b. t. h; n9 [2 F- Mvolcanic activity
5 L0 E' l( L' H& V" A0 jmechanism2 [( C3 ]2 N  V: J
volcanoes erupt
; k. ^" z& [0 C7 y* z/ w( Adisperse
* O: D6 |+ A" L2 h7 }2 Vparticle
& Q! }, k2 c+ q, m( q; f- lenergy exchange7 |4 y0 @) E) C
global climate change! _8 J% Q- u! b# A- O7 |
in all probability# U3 [  N+ T3 e2 b
complete explanation
. m" Y# Z5 Y2 B8 boperate
4 ^" n6 d! S2 Binvolve  m& M( T4 c5 A2 Y5 }: I

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! C/ X) U# I1 @2 K  a  x2 p2 p第三篇2 l( X$ a( U2 Y1 W/ M. w3 J$ l! d# B
Collecting mineral. e& J8 }, \$ c6 [, G
diverse
4 x* U* s6 @# u% }' }specimen  U* G  P: O- @; s7 ?6 J
pass it around
) {; o" L. w! ]9 {6 zabundant
3 }( \# u4 D" w( y, rdivided
7 R$ a3 e  c9 U$ Z6 q/ Dvary/variety/various+ R" J' Z  K3 X. S; `; `* m
volcanic rock
7 k# E$ _2 ]. }+ W# Q5 w' }- }- Usample$ v, a4 i* r' X
identify; ^9 m, J- T% L. S+ f3 z& w6 _
jewelry5 `% E2 t) z- t, K/ q
attractive: Y7 x8 B0 K; @  w2 ?2 d2 a/ b
rare9 D. a+ s8 V( o+ ]- G
slide

今天开始把场景分类训练拿来横听了