MK 001

聽(tīng)力音頻鏈接：

https://mp.weixin.qq.com/s/GL5iEb7pWLOuBibQbVVR3A

L3題目：

1.

What is the lecture mainly about?

?

A

The discovery of a new moon orbiting Saturn.

B

Methods used to observe the formation of Saturn’s moons.

C

Differences between planet formation and moon formation.

D

A theory about the formation of moons that orbit certain planets.

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2.

What is one important point the professor makes about Titan?

?

A

It was originally a moon of Uranus that was captured by Saturn.

B

It likely originated from the same material as Saturn.

C

Its gravity pulls Saturn’s rings outward.

D

It was produced by the impact of a moonlet colliding with Saturn.

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3.

According to the professor, what had astronomers been unable to account for until recently?

?

A

The reason for the unusual physical composition of Saturn’s moons.

B

The reason that smaller planets do not have multiple moons.

C

The reason for the size and position of many of the moons orbiting Saturn.

D

The reason that Saturn’s moons orbit in a different direction from its rings.

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4.

According to the professor, what is significant about the edge of one of Saturn’s outer rings?

?

A

Saturn’s gravitational pull is weak enough at the edge to allow moonlets to form there.

B

The speed at which material in the ring orbits Saturn varies there.

C

Light reflected by moonlets makes the edge brighter than the rest of the ring.

D

Large objects form beyond Saturn get pulled into the edge of the ring by the ring’s gravity.

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5.

According to the new model the professor discusses, what happens to many of Saturn’s moonlets as they move away from the planet？

?

A

They merge with other moons and become larger.

B

They move increasingly slowly.

C

They are captured back into Saturn’s ring system.

D

They are struck by other bodies and get broken up.

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6.

What is the professor’s opinion of the idea that the rings of Uranus and Neptune have become fainter due to moon formation?

?

A

It is the only hypothesis that can account for the degree of faintness observable today.

B

It is a reasonable conclusion to draw, but it should not be considered a complete explanation.

C

It cannot be confirmed until additional moons orbiting Uranus and Neptune are discovered.

D

The evidence suggesting that the rings were once brighter than they are today is not convincing.

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