Practice these TOEFL iBT listening tests to help you score high in the TOEFL Listening Section. Check the correct answers and audio transcripts below. This video is in the series of NEW TOEFL iBT Tests 2015.
Listen to part of a lecture in an astronomy class.
Professor
I’m sure y’all have been following the news about Mars. A lot of spacecraft have been
visiting the planet recently—some have gone into orbit around it, while others have
landed on it. And, they’ve sent back a . . . an abundance of data that’s reshaping our
knowledge . . . our vision of the planet in a lot of ways. Is there anything that you’ve
been particularly struck by in all the news reports?
Female Student
Well, they seem to mention water a lot, which kinda surprised me as I have this picture
in my head that Mars is dry . . . sorta dry and dead.
Professor
You’re not the only one. You know, for centuries, most of our knowledge of the planet
came from what we saw through telescopes so, obviously, it was pretty limited—and
our views of the planet were formed as much by writers . . . as they were by serious
scientists. When the first science-fiction stories came out, Mars was described as
being a lot like Earth except [pauses to let students finish his sentence]
Male Student
I know, the planet was red and, uh, the people were green. I’ve seen some of those old
movies [half laughing, half sarcastic] what were they thinking? I mean, really . . . they
[interrupted]
Professor [interrupting]
Well, it seems silly to us now but those ideas were quite imaginative and, occasionally,
scary in their time. Anyway, we began to rethink our image of Mars when the first
spacecraft flew by the planet in 1965 and sent pictures back to Earth. Those pictures
showed a planet that looked a lot more like our moon than Earth—lots of craters and
not much else. It was bitterly cold, it had a very thin atmosphere, and that atmosphere
was mostly carbon dioxide. So, the view of Mars after this first flyby mission was that
dry, dead planet that Lisa mentioned.
But, then there were more visits to the planet in the 1970’s—and this time the
spacecraft didn’t just fly by, they orbited . . . or landed. This allowed us to receive
much more detailed images of the planet and it turned out to be a pretty interesting
place. Mars had . . . has a lot more than craters—it has giant volcanoes and deep
canyons. It also showed signs of dried-up riverbeds and plains that had been formed
by massive floods. So we concluded that there must have been water on the planet at
one time—billions of years ago. Now, what does it take for water to exist?
Male Student
You need to have a warm enough temperature so that it doesn’t freeze.
Professor
That’s one thing—and the other is that you need enough atmospheric pressure, thick
enough air so that the water doesn’t instantly vaporize. The Mars we see today doesn’t
have either of those conditions—it is too cold and the air is too thin—but a long time
ago, there may have been a thicker atmosphere that created a greenhouse effect that
raised temperatures—and maybe that combination produced water on the surface of
the planet. So, maybe Mars wasn’t just a dead, boring rock—maybe, it was, uh, a fascinating
fossil that was once alive and dynamic—worthy of exploration. [Pause] Now,
let’s jump forward a few decades to the beginning of this century, and a new generation
of orbiters and landers that have been sent to Mars. Of course, the scientific instruments
now surveying Mars are far more sophisticated than the instruments of the
70’s, so we’re getting all kinds of new data for analysis. And, not surprisingly, that data
is challenging our notions of what Mars is like. Lisa, you mentioned that a lot of the
news reports talked about water—do you remember any of the details?
Female Student
Well, they were showing these pictures of these long, uh, cuts in the ground which
would be gullies here, I mean on Earth. They say that since, uh, gullies are usually
formed by water, it seems like they might be evidence that water still exists on Mars
but I didn’t get how that worked.
Professor
I’m not surprised. There’re a lot of theories . . . a lot of speculation . . . and some argue
the formations aren’t caused by water at all. But there’re some ingenious theories that
assume that there’s a lot of water right under the planet’s surface that somehow is
causing the gullies to form. If we could only get a lander there . . . but the gullies aren’t
in places where we can send landers yet. Anyway, if there is some kind of water activity,
it may change our view of the planet once again . . . to something that’s not dead,
not even a fossil, but rather a planet like Earth that undergoes cycles—think of our ice
ages—over long periods of time. Maybe Mars could sustain water again at some distant
date.
Correct Answers:
1. C
2. A
3. B,D
4. C
5. D
6. B
