难度等级：高
天文类是我个人认为托福听力中最难的一类话题，并且它考察的概率相当高（TPO2 L4 ，TPO3 L4，TPO5 L2，TPO13 L4，TPO14 L4，TPO18 L1，TPO19 L2 ，TPO21 L1，TPO22 L2，TPO24 L4），崩溃！
一方面天文学专业词汇对大多数同学来说非常陌生，另一方面天文类文章大多是在介绍某一种现象或者原理，由于缺乏天文学背景知识，这些信息间的逻辑很难被理顺，在听力过程中只能被动地记下几个单词，难以形成清晰的结构
接下来以TPO 05 Lecture 2为例，对天文类听力文本进行详细解析！
1.What is the main purpose of the lecture?
A. To explain why scientists disagree about the age of the Moon
B. To present arguments in favor of another Moon landing
C. To explain how scientists discovered a crater on the far side of the Moon
D. To review some findings of a recent mission to the Moon
2.What does the professor imply about the spacecraft Clementine?
A. It sent back the first color photographs of the Moon.
B. It was powered by solar energy.
C. It landed on the far side of the Moon.
D. It flew over the Moon’s polar regions.
3.Why does the professor mention the Moon’s mantle?
A. To explain why scientists believe that meteor impacts cannot affect the Moon’s mantle
B. To explain what kind of information scientists hope to obtain from the mantle
C. To point out that the Moon’s crust and mantle are made of similar materials
D. To point out that the Moon’s mantle and Earth’s mantle have different compositions
4.Why is the South Pole–Aitken Basin thought to be exceptionally old?
A. The walls of the Basin are more reflective than those of most other craters.
B. Testing of rocks from the Basin’s floor proved them to be as old as the Moon itself.
C. Many small craters have been detected at the bottom of the Basin.
D. A large amount of dust has been detected in and around the Basin.
5.Why does the professor consider it important to find out if water ice exists on the Moon? [Click on 2 answers.]
A. Water ice could be processed to provide breathable air for astronauts.
B. One component of water ice could be used as a fuel for rockets.
C. Water ice could contain evidence of primitive life on the Moon.
D. Water ice could be tested to find out what type of meteors crashed into the Moon.
5. What does the professor imply when he says this:
FEMALE STUDENT
But if we know around how old the Basin is, I’m not sure that’s reason enough to go to the Moon again.
MALE PROFESSOR
Oh, but such crude estimates…
A. The current age estimates for the South Pole–Aitken Basin are based on incorrect assumptions.
B. The technology to analyze Moon rocks has not advanced much since the days of the Moon landings.
C. Too few of the original Moon-rock samples were dated accurately.
D. Only by testing samples from South Pole–Aitken Basin can its age be precisely determined.
1B 2D 3B 4C 5AB 6D
Listen to part of a lecture in an astronomy class.
MALE PROFESSOR
Last week, we covered some arguments against going back to the Moon. But there are compelling reasons in favor of another Moon landing, too, um, not the least of which is trying to pinpoint the Moon’s age. （第一题答案出处）主旨-讨论再次登月不仅为确定月球年龄
We could do this, in theory, by studying an enormous impact crater（火山坑） known as the South Pole–Aitken Basin（盆地）. Ah, it’s located in the Moon’s south polar region. But, since it’s on the far side of the Moon, it can be seen only from space. Here’s an image of … we’ll call it the SPA Basin（South Pole Aitken Basin缩写）.介绍SPA Basin
This color-coded image of the SPA Basin—hhh, those aren’t its actual colors, obviously—uh, this image is from the mid-nineties, from an American spacecraft called Clementine.（第二题答案出处） Um, unlike earlier lunar missions, Clementine didn’t orbit（绕轨道而行） only around the Moon’s equator（赤道）. Its orbits enabled it to send back data to create this topographical（地质学的） map of…（比较影响听力的生词，如果能听出map的话对下文将有合理预期，更容易听懂内容）
Well, the gray-and-white area toward the bottom is the South Pole.
The purples and blues in the middle correspond to low elevations（海拔）—the SPA Basin itself.
Uh, the oranges and reds around it are higher elevations.
The Basin measures an amazing 2,500 kilometers in diameter, and its average depth is 12 kilometers. That makes it the biggest known crater in our solar system. And it may well be the oldest.介绍Clementine传回的topographical map，Basin是太阳系最大环形山，也可能是最老的（一定要掌握lecture和conversation中承上启下句的作用！！）
Y’know, planetary researchers love studying deep craters（环形山） to learn about the impacts that created them, um, how they redistributed（重分配） pieces of the planet’s crust. And, in this case, we especially want to know if any of the mantle（地幔）, the layer beneath the crust, was exposed by the impact. Not everyone agrees, but some experts are convinced that whatever created the SPA Basin did penetrate the Moon’s mantle. And we need to find out, because much more than the crust（地壳）, the mantle contains information about a planet’s or moon’s total composition. And that’s key to understanding planet formation. （第三题答案出处）um, Diane?对环形山的研究揭示其产生的作用-地壳重分布，暴露地壳下的地幔；总之该作用必穿透地幔，地幔是了解行星产生原因的关键（这一部分听力的难点在于生词很多，同时观点阐述不够清晰）
FEMALE STUDENT
So the only way to know the Basin’s age is to study its rocks directly?（Lecture中学生的话非常重要，一定一定要听清；但需要注意，学生的话虽然一定有关联性的，能起到提示和理清逻辑的作用，但答案主要还是出现在老师的话中）
MALE PROFESSOR
Well, from radio survey data, we know that the Basin contains lots of smaller craters. So it must be really old—around 4 billion years, give or take a few hundred million years. But that’s not very precise. If we had rock samples to study, we’d know whether these small craters were formed by impacts during the final stages of planetary formation, or if they resulted from later meteor showers.盆地有大量小的环形山，环形山是行星形成末期作用产生或由流星雨作用形成（第四题答案出处）
FEMALE STUDENT
But if we know around how old the Basin is, I’m not sure that’s reason enough to go to the Moon again.
MALE PROFESSOR
Oh, but such crude estimates…（第六题答案出处）mm, we can do better than that!
Besides, there’s other things worth investigating. Like, is there water ice on the Moon? Clementine’s data indicated that the wall of a south polar crater was more reflective than expected. So some experts think there’s probably ice there. Also, data from a later mission indicate significant concentrations of hydrogen, and by inference, water, less than a meter underground at both poles.
MALE STUDENT
If there’s water, how’d it get there? Underground rivers?
MALE PROFESSOR
We think meteors that crashed into the Moon, or tails of passing comets, may have introduced water molecules. Any water molecules that found their way to the floors of craters near the Moon’s poles, that water would be perpetually frozen because the floors of those craters are always in shadow. Uh, furthermore, if the water ice was mixed in with rock and dust, it’d be protected from evaporation.
FEMALE STUDENT
So, are you saying there might be primitive life on the Moon?
MALE PROFESSOR
Uh, that’s not my point at all! Um, OK, say there is water ice on the Moon. That would be of very practical value for a future Moon base for astronauts. Uh, water ice could be melted and purified for drinking. It could also be broken down into its component parts—oxygen and hydrogen. Oxygen could be used to breathe. And hydrogen could be turned into fuel, rocket fuel. （第五题答案出处）So, water ice could enable the creation of a self-sustaining Moon base someday, a mining camp, perhaps, or, uh, a departure point for further space exploration.
MALE STUDENT
But hauling tons of equipment to the Moon to make fuel and build a life-support system for a Moon base…wouldn’t that be too expensive?
MALE PROFESSOR
A permanent base uh, may be a ways off,（很久之后） but we shouldn’t have to wait for that. The dust at the bottom of the SPA Basin really does have a fascinating story to tell. What I wouldn’t give for a few samples of it!
这篇文章的特点：1 逻辑层层递进，记录笔记需要快且细才能避免遗漏逻辑点 2 开头出现大量专业名词部分很容易因为生词的原因听不懂、抓不到重点
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