2021年11月20日雅思考试机经回忆完整版(4)

2023-06-04 12:55:57 来源：金宝搏188入口

2021年11月20日雅思考试机经回忆完整版(4) 关于这个问题下面小编就来为各个考生解答下。

2021年11月20日雅思考试机经回忆完整版(4)

2021.11.20

READING

Passage 1

Topic

The oldest leather shoes in the world

1-13为填空题

1.oil

2.暂缺

3. Cord

4-13.暂缺

Passage 2

Topic

The Plan to Bring an Asteroid to Earth

A:Send a robot into space. Grab an asteroid. Bring it back to Earth orbit This may sound like a crazy plan, but it was discussed quite seriously last week by a group of scientists and

engineers at the alifomia Instiute of Technology. The four-day workshop was dedicated to investigating the feasibility and requirements of capturing a near-Earth asteroid, bringing it

closer to our planet and using it as a base for future manned spacetight missins.

This is not something the scientists are imagining could be done some day off in the future.

This is possible with the technology we have today and could be accomplished within a decade.

"Once you get over the initial reaction- "You want to do what?!'一it actully starts to seem like a reasonable idea," said engineer John Brophy from NASAS Jet Propulsion Laboratory,

who helped organize the workshop.

B: Though reamanging the heavens may seem an excessive undertaking, the mission has its merits. Parking an asteroid in a gravitatinally neutral spot between the Earth and the sun, known as a Lagrange point, would provide a stationary base fom which to launch missions further into space. There are several advantages to this. For one, launching materials from Earth requires a lot of power, fuel, and consequently money, to get out of our planet's deep gravity well. Resources mined from an asteroid with very litle gravitational pull could be easily shutled around the solar system.

And many asteroids have a lot to offer. Some are full of metals such as iron, which can be used to build space- based ha bitats while others are up to one-quarter water, which would be

either used for liesupport or broken down into hydrogen and oxygen to make fuel. As well, asteroid regolth placed around a spacep hull would shield it against radiation fom deep space, alowing safer travel to other planets.

An asteroid could be an altemative to setting up camp on the moon, or complement a moon base with more resouroes for heading further out in the solar system, said engineer Louis Friedman, cofounder of the Planetary Societly and another co-organizer of the Callech workshop.

C: There's also the potential for mining asterold materials to bring back to Earth. Even a small asteroid contains roughly 30 times the amount of metals mined over all of human history, with an estimated worth of $70 tllion. And astronomers would have the chance to get a close-up look at one of the solar system's earliest rlis, generating important sclentific

data.

Though technically feasible, budging such a hefty target - - with a mass in excess of a millin tons一would not be easy.

"You're moving the largest mother lode imaginable,"E said former astronaut Rusty Schweickart, cofounder of the B612 Foundation, an organization dedicated to protecting Earth from asteroid strikesMost asteroids are iregular chunks of rock that spin chatically along rregular axes. Engineers would need to be absolutely certain they could control such a potentially dangerous object "It's the opposite of planetary defense; if you do something wrong you have a Tunguska event," said engineer Marco Tantardini from the Planetary Society, rering to the powerful 1908 explosion above a remole Russian region thought to have been caused by a meteoroid or comet Of course, any asteroid brought back under the proposed plan would be too small to cause a repeat of such an event.

D: Sil, these obstacles are like catnip to engineers, who love to go over every potential difiulty in order to solve it. Actually executing the asteroid retrieval plan would help demonstrate and greatly expand mankind's space-based engneering capabitties, said Friedman. For instance, the mission would teach engineers how to capture an uncooperaive target, which could be good practice for future planetary defense missions, he added. And if the challenges for a large asteroid seem too daunting, researchers could always start with a smaler asteroid, perhaps six to 30 feet across. Gradually larger objects could be part of a campaign where engineers learm to deal with progressively greater complcalions.

E: No matter the size of the asteroid, these plans would require hety investments. Even capturing a small asteroid would consume at least a blion dolars and anything larger would

be a mufibilindollar endeavor. Convincing taxpayers to foot such a bil could be tricky. Considering the resources available in any asteroid, private industry might be interested in

getting involved. One possible mission would be to simply execute the first part of the plan pushing the asteroid to nearEarth orbit 一and then convene a commercial competition

inting arnyone who wants to develop the capabilies to reach and mine the object.

Though the undertaking might be soentifally. exciting, this. wouldn't be the primary motivalion. An asteroid would provide great insight int the solar system's formation, it's not

enough to justify the expense of bringing one to Earth. Any interesting science can be done much cheaper with an unmanned robotic spacecraft, said chemist Joseph A Nuth from

NASA's Goddard Spaceflight Center."Ulimately, we would be developing this target in order to help move out into the solar system," Brophy said.

题目方面

14-18为list of headings

A. An available goal, not a dream

B. What the asterold can offer

C. Need skill and care

D. Start from a smaller challenge

E. Seek for support

14-18暂缺

19-21为匹配题

19. Louis Friedman B

20. Rusty Schweickart C