【推荐1】Scientists have discovered a "monster black hole" so massive that, in theory, it shouldn't exist

It’s a stellar black hole---the type that forms after stars die, collapse, and explode. Researchers had previously believed that the size limit was no more than 20 times the mass of our sun because 8S these stars die, they lose most of their mass through explosions that expel matter and gas swept away by stellar winds

This theory has now been toppled by LB-1, the newly discovered black hole. Located about 15.000 light years away, it has a mass 70 times greater than our sun, according to a press release from the Chinese Academy of Sciences.

The findings were published by Chinese researchers in the journal Nature on Wednesday.

"Black boles of such mass should not even exist in our galaxy, according to most of the current models of stellar evolution," said Liu Jifeng, head of the team that made the discovery. "LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation."

Scientists are now scratching their heads at how LB-1 got so huge.

The Chinese team has proposed a number of theories. LB-1' sheer size suggests that it “was not formed from the collapse of only one star," the study said--- instead, it could potentially be two smaller black holes orbiting each other.

Another possibility is that it formed from “fallback supermova.” This is when a supernoma---the last stage of an exploding star---ejects material during the explosion, which then falls back into the supernova, creating a black hole.

This fallback formation is theoretically possible, but scientists have never been able to prove or observe it. If this is how LB-1 formed, then we may have "direct evidence for this process” for the first time, the study said.

There are several types of black holes and stellar black holes like LB-1 are on the smaller side, according to NASA. Supermassive black holes are much bigger---they can be billions of times the mass of our sun,

Scientists believe supermassive black holes may be connected to the formation of galaxies, as they often exist at the center of the mass star stems but it is still not clear exactly how, or which form first.

1. Why does the writer write the article?

A．To report the great achievement Chinese scientists have made in black hole theory,

B．To inform the readers of the basic knowledge about the black hole,

C．To share with the readers the new development of the black hole discovery,

D．To demonstrate the significance of discovering new black holes for science.

2. Which of the following about LB-1 is true to the passage?

A．It is the biggest black hole ever discovered,

B．It lost only a small part of its mass through explosion.

C．It couldn't have been formed from the collapse of one star,

D．Its discovery may lead to some breakthrough in the “fallback formation theory".

3. Which of the following is right according to the passage?

A．If the sun in our galaxy dies some of its mass will be taken away by stellar winds.

B．A massive supernova will be formed and then exploded if the sun in our galaxy dies.

C．"The Milky Way" was formed after a supermassive black hole collapsed and exploded.

D．If “the Milky Way" dies, a supermassive black hole will be formed after its death.

【推荐2】Nine years ago, when the closest and largest full moon fell on March 19, 2011, many people used the term, “supermoon”, which we had never heard before. In 2012, we heard this term again to describe the year’s closest full moon on May 6, 2012. Supermoons also appeared in 2013, 2014, 2015, 2017 and 2019.

What does “supermoon” mean exactly? And how special was the March 19, 2011 supermoon?

The word “supermoon” didn’t come from astronomy. Instead, it came from astrology (占星学). In 1979, astrologer Richard Nolle defined it as a new or full moon which occurs at or near its closest point to the earth in its orbit. In short, the earth, moon and sun are all in a line, with the moon at its nearest point to the earth.

And the full moon of March 19, 2011 was the largest moon of that year. This “supermoon” was at perigee (近地点)—its closest point to the earth in its orbit. It was bigger and brighter than other full moons of 2011. Astronomers call this sort of close full moon a perigee full moon.

That doesn’t sound very special, does it? In fact, the March 2011 full moon lined up much closer to perigee than Nolle’s original definition. But were you able to notice with your eyes alone that this full moon was bigger or brighter than usual? Astronomers said no. But it was fun to stand outside under this full moon and know that the moon was closer than ever.

In 2019, there were three supermoons. The first supermoon of 2019 was the Super Blood Wolf Moon on January 21, which occurred with a total lunar eclipse (月全食) at the same time, also known as a “blood moon”. The second supermoon of 2019 was on February 19, also called the Snow Moon, which was the closest full moon of the year. The third and final supermoon of 2019, known by Native Americans as the Worm Moon, occurred on March 21. It fell on the day of the vernal equinox (春分), which signals the end of winter and the beginning of spring.

1. What type of moon is a “supermoon”?

A．A full moon.	B．A new moon.
C．A full moon at perigee.	D．Any full moon in 2011.

2. What do we know about the supermoon of March 2011?

A．It was the first full moon in 2011.

B．It was in the closest orbit to the sun.

C．It was brighter than any other full moon in 2011.

D．It was at its furthest point to the earth.

3. What can we learn from the underlined sentences in the fifth paragraph about a supermoon and an ordinary full moon?

A．They can appear in the sky at the same time.

B．Only astronomers can see them.

C．The supermoon is as large as an ordinary full moon.

D．People can’t tell the difference between them with the naked eye.

4. The third supermoon of 2019 ________.

A．was called the Super Blood Wolf Moon

B．was the closest full moon of the year

C．was found by Native Americans first

D．occurred on the day of the vernal equinox

【推荐3】Many of us have read stories or seen films about space creatures(生物). They come to the Earth in spaceships that look like flying saucers. These space­creatures do not look like human beings at all, but they are usually very intelligent(聪明). In one film, they were tiny little men with large heads. When they landed on the Earth, they knew exactly what to do. They went straight to the President's palace and made him their prisoner!

The stories about space creatures are, of course, not true. Space­creatures exist only in story books and films, just like giants and fairies. But many scientists are asking this question--“Is there life on other planets?” There are millions of planets in the universe, and the Earth is just one of them. Could there be living things on other planets? Many people believe that the other planets in the universe are most suitable for living things.

Are scientists sure that there is no life on other planets?

At this stage we still cannot be sure. All the planets, except the moon and Mars, are so far away that it will take hundreds of years for our spaceships to reach them.

1. The BEST title for the passage is“________”.

A．Scientific Wonders- Space­creatures	B．Is There Life on Other Planets?
C．Are Scientists Sure?	D．Stories about Space­creatures

2. It is impossible for scientists to know about other planets in the universe because________.

A．all the planets, except the moon, are so far away that it will take hundreds of years for our spaceships to reach them

B．all the planets are too far to reach

C．all the planets,except the moon and Mars, are so far away that it will take hundreds of years for our spaceships to reach them

D．all the planets are only too far to reach

3. Which of the following statements is NOT true according to the passage?

A．The stories about space­creatures are true.	B．Space­creatures are in stories.
C．Space­creatures are in films.	D．Many scientists are asking if there is life on other planets.

4. In the passage “straight” means________.

A．upright (直立的)	B．level
C．directly	D．honest

【推荐2】The traditional distinction between products that satisfy needs and those that satisfy wants is no longer adequate to describe classes of products. In today’s prosperous societies, the distinction has become unclear because so many wants have been turned into needs. A writer, for instance, can work with paper and pencils. These are legal needs for the task. But the work can be done more quickly and efficiently with a word processor. Thus a computer is soon viewed as a need rather than a want.
In the field of marketing, consumer goods are classed according to the way in which they are purchased. The two main classes are convenience goods and shopping goods. Two lesser types are specialty goods and unsought(主动提供的) goods. It must be emphasized that all of these types are based on the way shoppers think about products, not on the nature of the products themselves. What is regarded as a convenience item in France (wine, for example) should be a specialty goods in the United States.
People do not spend a great deal of time shopping for such convenience items as groceries, newspapers, toothpaste, aspirin, and candy. The buying of convenience goods may be done routinely, as some families buy groceries once a week. Such regularly purchased items are called staples. Sometimes convenience products are bought without enough thinking; someone has a sudden desire for an ice cream sundae(圣代) on a hot day. Or they may be purchased as emergency items.
Shopping goods are items for which customers search. They compare prices, quality, and styles, and may visit a number of stores before making a decision. Buying an automobile is often done this way.
Shopping goods fall into two classes; those that are recognized as basically the same and those that are regarded as different. Items that are looked upon as basically the same include such things as home appliances, television sets, and automobiles. Having decided on the model desired, the customer is primarily interested in getting the item at the most favorable price. Items regarded as essentially different include clothing, furniture, and dishes. Quality, style and fashion will either take precedence(优先) over price, or they will not matter at all.
1. It can be learned from the first paragraph that ______.

A．a writer needs a word processor

B．needs and wants can’t be separated clearly

C．the way to distinguish the products is unimportant

D．a computer is a need rather than a want

2. The example of wine is used to illustrate that ______.

A．goods are classified differently in different countries

B．the types of the product lie on the people rather than its nature

C．Frenchmen often drink but Americans sometimes do

D．one product may belong to many types

3. Staples are items that ______.

A．are convenient to purchase

B．are purchased without enough thinking

C．people “want but don’t need”

D．people are in constant need of

4. Shopping goods that are considered as basically the same are those that ______.

A．consumers don’t care where to buy them

B．consumers spend much time searching for

C．satisfy similar needs of the consumer

D．can be found in nearly every shop