Scientists could see many things that most people would to see.A. fellB. failC. fallD. f

A. feel

B. fail

C. fall

D. fill

They could see there was something wrong with both watches. They observed them for several hours before speaking to each other. They both silently found that the German watch was losing 60 minutes and the Japanese are doubled that.

The scientist with the Japanese watch then slowly raised his head and said, "Both watch are out of work, but my watch is right more often than yours, so it's better." The scientist with the German watch went home without saying a word.

The two scientists were quarrelling at the beginning of the story, because ______.

A．the Japanese watch was better

B．the German watch was better

C．each of them thought his own watch was better than the other's

D．both the watches were wrong

根据下列材料请回答 31～35 题：

A

Now satellites are helping to forecast the weather．They are in space，and they can reach any part of the world．The satellites take pictures of the atmosphere(大气)，because this is where the weather form．They send these pictures to the weather stations．So meteorologists(气象学家)can see the weather of any part of the world．From the pictures，the scientists can often say how the weather will change．

Today，nearly five hundred weather stations in sixty countries receive satellite pictures．When they receive new pictures，the meteorologists compare them with earlier ones．Perhaps they may find that the clouds have changed during the last few hours．This may mean that the weather on the ground may soon change，too．In their next weather forecast，the meteorologists can say this．

So the weather satellites are a great help to the meteorologists．Before satellites were invented，the scientists could forecast the weather for about 24 0r 48 hours．Now they can make good forecasts for three or five days．Soon，perhaps，they may be able to forecast the weather for a week or more ahead．

第 31 题 Satellites travel______．

A．in space

B．in the atmosphere

C．above the ground

D．above space

Passage Three

A group of scientists rowing toward the center of a lake saw something shocking. They turned back as fast as they could. What had they seen.？ The lake was boiling!

The group was investigating a crater lake in the mountains of St. Vincent. A crater lake is the mouth of a volcano that has been dormant for some time and has filled with water.

This particular crater was the tip of a volcano called Soufriere, which erupted last in 1902. Since that time, it had not shown any signs of action. But in the fall of 1971, mountain climbers who had hiked near the lake returned to the lowlands with strange stories. They said the water had turned yellow and was giving off a smell like burnt eggs. A seething fog was rising from the lake's surface.

Local scientists rushed to Soufriere to see if this might be the beginning of a new volcanic explosion. They found a huge black mass in the middle of the water. It was a great blob 1,000 feet long and 300 feet wide. Lava had pushed up through the bottom of the lake and formed a new island.

The investigators wanted to make sure that the volcano was safe, and that the lava would not over- flow into the surrounding countryside. But they could never reach the island to study it, because the lava was so hot that the water around it bubbled and boiled.

44. This passage is about ______.

A. mountain climbing

B. a boiling lake

C. a new volcanic island

D. a mysterious blob

根据短文，回答{TSE}题 The future of space exploration depends on many things．It depends on how technology evolves how Dolitical forces shape competition and partnerships between nations，and how important the public feels spaceexdloration is．The near future will see the continuation of human space flight in Earth’s orbit and unpiloted space mght within the so1ar systern．Piloted space flight to other planets，or even back to the moon, still seems far away．Any flight to other solarsystems is even more distant'but a huge adVance m space technology could drive space exploration into realms currently explored only by science fiction．The 1968 film 2001：A SpacP Odyssey depicted commercial shuttles flying to and from a giant wheel- shoped space station in orbh around Earth，bases on the moon，and a piloted mission to Jupiter. The real space activities of 2001 will not match this cinematic vision，but the 21st century will see a continuation of efforts to transform humanity into a spacefaring species．Perhaps the most difficult problem space planners face is how to finance a vigorous program of piloted space exploration.in Earth’s orbit and beyond．In l998 no single government or international enterprise had plans to send people back to the moon，much less to Mars．Suchmissions are unlikely to happen until the perceived value exceeds their cosLOne belief shared by a number of space exploration experts is that future lunar and Martian expeditions sheluld be aimed at creating permanent settlements．The residents of such outposts would have to“live off the land”．0btaining such necessities as oxygen and water fromthe harsh environment．On the moon，pioneers could obtain oxygen by heating lunar soil．In l998 the Lunar Prospector discovered evidence ofsignificant deposits of ice，a valuable resource for settlers，mixed with soll at the lunar poles．On Mars，oxygen could be extracteel from the atmosphere and water could come from buried deposits of ice．The future of piloted lunar and planetary exploration remains largely unknown．Most space exploration scientists believe that people will be on the moon and Mars by the middle of the 21st century，but how they get there，and the nature of their visits，is a subject of continuing debate．Clearly，key advances will need to be made in lowering the cost of getting people off Earth，the first step in any human voyage to other worlds．{TS}A flight to other solar systems will be made nlore possible by__________．[A]technological breakthroughs[B] international cooperation[C]market competition[D]public pressure

Black Holes Trigger Stars to Self-Destruct

Scientists have long understood that super massive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hole's gravity pulls harder on the nearest part of the star, an imbalance that pulls 'the star apart over a period of minutes or hours, once it gets close enough.

Scientists say this uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, Francel, carried out computer simulations of the final moments of such an unfortunate star's life, as it veered towards a super massive black hole.

When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur.

The new simulations investigated the effects of shock waves in detail, and found that even when their effects are included, the conditions favor a nuclear explosion. "There will be an explosion of the star—it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star's matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star's matter out of the black hole's reach, he says.

The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays.

If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Halpern of Columbia University in New York, US2. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says.

Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it's something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US3, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process.

Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage？

A．The black hole could tear apart the star.

B．The black bole could trigger a nuclear explosion in the star.

C．The black hole could dwindle its size considerably.

D．The black hole could devour the star.

Inside, the area that normally had seats had become a long white tunnel. Heavily padded (填塞) from floor to ceiling, it looked a bit strange. There were almost no windows, but lights along the padded walls illuminated it. Most of the seats had been taken out, apart from a few at the back, where the young scientists quickly took their places with a look of fear.

For 12 months, science students from across the continents had competed to win a place on the flight at the invitation of the European Space Agency. The challenge had been to suggest imaginative experiments to be conducted in weightless conditions.

For the next two hours, the flight resembled that of an enormous bird which had lost its reason, shooting upwards towards the heavens before rushing .towards Earth. The invention was to achieve weightlessness for a few seconds.

The aircraft took off smoothly enough, but any feelings that I and the young scientists had that we were on anything like a scheduled passenger service were quickly dismissed when the pilot put the plane into a 45-degree climb which lasted around 20 seconds. Then the engines cut out and we became weightless. Everything became confused and left or right, up or down no longer had any meaning. After ten seconds of free-fall descent(下降) the pilot pulled the aircraft out of its nosedive. The return of gravity was less immediate than its loss, but was still sudden enough to ensure that some students came down with a bump.

Each time the pilot cut the engines and we became weightless, a new team conducted its experiment. First it was the Dutch who wanted to discover how it is that eats always land on their feet. Then the German team who conducted a successful experiment on a traditional building method to see if it could be used for building a future space station. The Americans had an idea to create solar sails that could be used by satellites.

After two hours of going up and down in the lane doing their experiments, the predominant feeling was one of excitement rather than sickness. Most of the students thought it was an unforgettable experience and one they would be keen to repeat.

What did the writer say about the plane？

A．It had no seats.

B．It was painted white.

C．It had no windows.

D．The outside was misleading.

. During vigorous exercise, our muscles tire as they run out of fuel and build up waste products. Muscle performance can also be affected by a phenomenon called "central fatigue," in which an imbalance in the body's chemical messengers prevents the central nervous system from directing muscle movements effectively. It was not known, however, whether central fatigue might also affect motor systems not directly involved in the exercise itself—such as those that move the eyes. To find out, researchers gave 11 volunteers a carbohydrate solution either with a moderate dose of caffeine—which is known to stimulate the central nervous system—or as a placebo without, during 3 hours of cycling. After exercising, the scientists tested the cyclists with eye-tracking cameras to see how well their brains could still control their visual system. The team found that exercise reduced the speed of rapid eye movements by about 8%, preventing their ability to capture new visual information. The caffeine—the equivalent of two strong cups of coffee—was sufficient to counteract this effect, with some cyclists even displaying increased eye movement speeds, the team reports today in Scientific Reports. So it might be a good idea to get someone else to drive you home after that marathon.