toefltrick
About listening
- 听力（lecture）的最后很关键！经常出题目，已经吃了好几次亏！
By tracing these materials to distant source locations and establishing reliable dates for them, we can identify ancient trading patterns, which is valuable information for archaeologists.
TPO62 Lecture2
Listen to part of a lecture in an astronomy class. So we pretty much know how the biggest stars die. When a massive star reaches the end of its existence, it explodes, sending out a huge blast of energy, which then fades to invisibility within a few weeks or months. When a giant star explodes like this, it’s called a supernova. To the naked eye. A supernova appears to be a bright new star, but it’s not a new star, it’s a dying star. However, the shock waves from a supernova excite nearby clouds of hydrogen gas, causing them to compress which does form new stars. And that process emits a distinctive type of radiation.
Now, a particular interest to us today is that the same type of radiation has been observed in places where galaxies have collided. In those same areas, we’ve also observed a high rate of new star formation. So not surprisingly, we’ve had a theory that colliding galaxies caused the new star formation, but there was no direct evidence that is until recently, when some European astronomers found clouds of excited hydrogen gas that could only have been caused by shock waves from a pair of colliding galaxies. We used to think of galaxies as isolated systems like islands in the sea of space.
We know that they’re always moving usually in clusters. I think about all the gravitational forces involved. We’re talking about huge systems of stars and gas and dust. Since the average separation between galaxies is only about 20 times their diameter, it isn’t surprising that they often meet. We call it an encounter, and they meet in a variety of ways. Mergers, for example, they are the most extreme kinds of Galaxy encounters. A merger is when two galaxies meet, and they don’t have enough momentum to keep going on their separate ways. They merge becoming one Galaxy. Usually a larger Galaxy will absorb sort of swallow a smaller one. This can trigger huge areas of star formation as enormous clouds of gas from the two galaxies collide and collapse into very active star forming regions. Collisions are less violent than mergers. That is they create fewer or relatively less active areas of star formation. The galaxies pass through each other, each going its separate way.
After they collide, the collision sends out a ripple of energy into space, plowing gas and dust in front of it. Your textbook has a great picture of a Galaxy collision taken by the Hubble Space Telescope. See the cartwheel Galaxy on the left. It looks like the ripples in a pond after his stones been tossed in. That’s because one of the small galaxies on the rights passed through it, that bright ring around it, that’s where colliding and compressing gas is forming stars, but which Galaxy collided with it? The one on the upper right has been stripped of gas and dust, which is one clear sign that there’s been a collision. But the one on the bottoms showing a lot of new star formation, which is also evidence of a collision. We’re just not sure.
Finally, we have interactions in this type of encounter the galaxies, exchange, gas and dust, but don’t actually collide. Many astronomers believe that the trail of gas and dust that stretches from our Milky Way Galaxy to one nearby is the result of an interaction. When the gravitational forces of the Milky Way pulled some dust and gas off of the other Galaxy. What about stars? Do they ever collide? Actually almost never. Stars are very small compared to the size of a Galaxy, and they’re pretty far apart from each other small stars. That term is relative, isn’t it? It’s hard to imagine the massive distances we’re talking about here. Even encounter seems like an odd term as these events take a long time. We’re talking billions of years, which is why most of what we theorize about comes from computer simulations. Otherwise, all we’d see is a sort of freeze frame of whatever stage the encounter is in a single picture out of a long sequence of events.
But I mentioned some new evidence that’s come from a pair of galaxies called the antennae. The antennae are at an early stage of encounter. What will probably be a merger and excited hydrogen gas has been found in the regions where the two galaxies overlap. We know because that distinctive radiation signature is present. We know that there aren’t enough supernova to explain the radiation. The only other possibility is that we’re seeing the result of shock waves produced by the collision of these two galaxies.
TPO65 C2
isten to a conversation between a student and his professor.
Student: Professor Anderson. I really don’t want this to come out sounding all wrong. Like I really appreciate you seeing me, taking the time and everything.
Professor: What is it Michael?
Student: Well… um, it’s about the modern drama course.
Professor: There’s a lot of work in that class. l hear about it all the time from students. So let me guess is the reading too difficult? Assignments too long?
Student: No, actually, it’s just. I thought we’d be reading different stuff like more modern.
Professor: Um. What we are reading is very modern. Quintessentially modern, mean… don’t you think Samuel Beckett works are modern?
Student: Frankly, no. 1-C l mean, I think he’s more modern than Chekhov, but he wrote his best stuff over 50 years ago.
Professor: I see, so by modern, you mean…2-D
Student: Like David Mamet. I mean he’s alive and writing right now.
Professor: I think what you mean is you’d like to read more contemporary playwrights, is that it?
Student: Contemporary modern, basically the same thing, right?
Professor: Well, we do use them interchangeably in an everyday speech. But in terms of the history of drama, modern generally means the early in mid 20th century. The first six decades Or SO, but really it has less to do with this span of time and more to do with the work of a few very important playwrights.
Student: can see that these people may have been revolutionary artists for their times, But are their ideas like still relevant today? mean, are they like old hat.
Professor: I think that if you take a closer look at contemporary playwrights like David Mamet, you’d realize that what he’s doing iS not all that different from what say, like earlier playwrights like Beckett, or even Chekhov, for example, was doing and it’s almost impossible to imagine that David Mamet could be writing the way he does, if 计 hadn’t been for those earlier playwrights.
Student: Can you give me an example?
Professor: Um, Mamet’s use of language and the rhythm of the dialogue, like Beckett. Rhythm was an important element in his dialogue. There’s one particular play written by Mamet’s called the Cryptogram, which is a great example of this.3-B Let’s just say that Beckett looms behind all of Mamet’s plays, but this one, the Cryptogram, it’s not only Mamet’s language that recalls Beckett, but aso the predicarent in which Mamet’s characters find themselves. Yeah, really Michael, I don’t think the course description is misleading. This is a course on modern drama. And that is what we are reading.5 l mean, if you’re interested in contemporary dramatist and you can, i you want to write your first paper on a contemporary playwright, but only if it’s a comparison with the work of an earlier playwright. I think that would be a good exercise. And it might even help you resolve some of the problems we talked about today. 4