1 . Astronomers have discovered the cause of the “Great Dimming（暗淡）of Betelgeuse” ： a cloud of dust partly hiding it from us.
As one of the largest stars that can be seen by the naked eye, the red supergiant star Betelgeuse is a familiar sight to professional and amateur astronomers alike. That’s perhaps why it was so surprising when the star’s brightness started to drop in October 2019.
This sudden drop caused a speculation that Betelgeuse was about to go supernova（超新星）—that is, reach the end of its life as a red supergiant, break away, and then bounce into a burning explosion so bright that we’d even be able to see it in the daytime. It wasn’t immediately clear to astronomers whether or not that was the case, since a supernova hasn’t been observed in our Galaxy since astronomer Johannes Kepler saw one in 1604.
But it never happened, and by April 2020, Betelgeuse was back to its normal brightness. Now, images of the star, taken with the European Southern Observatory’s Very Large Telescope, along with data from the GRAVITY instrument, have shown what happened to it.
The surface of Betelgeuse is always changing. Giant bubbles（气泡）of gas grow, become smaller and move around within the star, and occasionally it lets one go. Before the Great Dimming began, Betelgeuse let one of these bubbles go. Then a part of the star’s surface cooled down, and this temperature drop allowed the gas to cool enough to turn into solid dust.
The cloud of dust partly hid Betelgeuse from the Earth, particularly in the southern part.
“The dust getting away from cool evolved stars, such as the eruption we’ve just witnessed, could go on to become the building blocks of terrestrial planets（类地行星）and life,” said Emily Cannon, a PhD student at KU Leuven. “Looking up at the stars at night, we’ll feel these tiny, shining dots of light seem permanent. The dimming of Betelgeuse breaks this idea.”
1. Why do astronomers feel amazed at the “Great Dimming of Betelgeuse”?| A．Because Betelgeuse is familiar to them. |
| B．Because Betelgeuse was ready to welcome a great explosion. |
| C．Because Betelgeuse’s brightness started to drop in October 2019. |
| D．Because Betelgeuse was blocked from us by a cloud of dust partly. |
| A．Admission. | B．Concept. | C．Principle. | D．Assumption. |
| A．The dust from cool evolved stars. | B．The shining dots of light. |
| C．The changing appearance of a star. | D．The cooling down of a star. |
| A．A supernova transformed from Betelgeuse. |
| B．Terrestrial planets and life found by scientists. |
| C．The idea proved wrong by the dimming of Betelgeuse. |
| D．The “Great Dimming of Betelgeuse” caused by a cloud of dust. |
2 . The year 2021 saw some important developments in the exploration of Mars as well as a rise in space tourism.
In February, NASA announced（宣布）that its Mars explorer. Perseverance. landed successfully on the Red Planet, whose mission（任务、使命）was to search for signs of ancient life.
Perseverance landed in an area of Mars called Jezero Crater. Scientists believe the area contains a large ancient lake bed. Scientists believe if life ever existed on Mars, it would have been present 3 to 4 billion years ago, when water flowed on the planet. Perseverance also carried to Mars a small experimental helicopter（直升飞机）named Ingenuity, which had successfully completed a takeoff and landing on the planet.
This year. both China and the United Arab Emirates（UAE）sent their first spacecraft to Mars.
In May, China announced that its Tianwen—I spacecraft had successfully landed on Mars after a seven-month trip. The spacecraft landed at Utopia Planitia. a large flat area in the northern half of the planet. The six wheeled explorer is studying the planet's surface soil and atmosphere in search for signs of ancient life. The UAE's Hope Probe spacecraft was sent to an extremely high orbit（轨道）above Mars to study the planet. Unlike other explorations, the UAE's project aims to study atmospheric conditions around Mars.
In July, British billionaire Richard Branson flew into space on a rocket plane built b Virgin Galactic. the space tourism company he founded. Branson joined two pilots on the flight. Virgin Galactic aims to fly private citizens to space to experience a few minutes of weightlessness and observe Earth. Over a week later. Amazon boss Jeff Bezos flew to space on a rocket built by his company. Blue Origin. The flights by Branson and Bezos officially created a new industry that promises any citizen the chance to visit space. Such trips will be costly. however. Virgin Galactic's price for a single flight is $250,000. Blue Origin has not announced its price.
1. Which of the following about "Perseverance" is true?| A．It found a water source in a lake. | B．It landed at Utopia Planitia on Mars. |
| C．It found life present 3 to 4 billion years ago. | D．It was designed to search for signs of ancient life. |
| A．It carried a helicopter to the Mars. | B．It studied the Mars' surface soil. |
| C．It mainly studied the Mars' atmosphere. | D．It landed on the Mars to do experiments |
| A．The common people can afford to travel to space. |
| B．The rich tend to show more interest in space exploration. |
| C．Space tourism is far too expensive to afford for the most. |
| D．Tourists can experience a few hours of weightlessness. |
| A．Space Tourism is Appreciated by the Public |
| B．2021 Saw Advances on Mars and Rise in Space Tourism. |
| C．Space Exploration on Mars Shows Signs of Ancient Life. |
| D．2021 Saw Significant Technological Advances in IT. |
