题目内容
The massive 8.8 quake, the seventh strongest in recorded history, hit Chile（智利） and should have shortened the length of an Earth day by 1.26 milliseconds. More impressive is how much the quake shifted the Earth’s axis（地轴）.
The computer model used to determine the effects of the Chile earthquake effect also found that it should have moved the Earth’s figure axis by about 8 cm. The Earth’s figure axis is not the same as its north-south axis, which Earth turns around once every day at a speed of about 1,604 kph. The figure axis is the axis around which the Earth’s mass is balanced. It is offset（偏离）from the Earth’s north-south axis by about 10 meters.
Strong earthquakes can change Earth’s days and its axis. The 9.1 Sumatran earthquake in 2004, which set off a deadly tsunami（海啸）, should have shortened Earth’s days by 0.0068 milliseconds and shifted its axis by about 7cm.
One Earth day is about 24 hours long. Over the course of a year, the length of a day normally changes gradually by one millisecond. It increases in the winter when Earth moves more slowly, and decreases in the summer.
The Chile earthquake was much smaller than the Sumatran quake, but its effects on the Earth are larger because of its location. The fault（断层） responsible for the 2010 Chile quake also cuts through Earth at a larger angle(角度) than the Sumatran quake’s fault. This makes the Chile fault more effective in moving the Earth’s mass vertically and hence more effective in shifting the Earth’s figure axis.
The findings are based on early data available on the Chile earthquake. The Chile earthquake has killed more than 700 people and caused widespread damage in the South American country.
1. What’s the biggest problem caused by the Chile quake?
A. It is the seventh strongest in recorded history.
B. It should have shortened the length of an Earth day.
C. It shifted the Earth’s axis.
D. It made the day longer on Earth.
2. Comparing the Sumatran earthquake with the Chile earthquake, we know that ______.
A. the Sumatran earthquake had more effect on Earth
B. the location of the Chile earthquake is responsible for its larger effects on Earth
C. the Sumatran earthquake was less destructive
D. the Chile earthquake fault changed the Earth’s mass
3. What does the word “It” in the 4th paragraph refer to?
A. The length of a day. B. The axis.
C. One millisecond. D. The change of the day.
4. This article is most probably taken from .
A. A travel book B. A fiction
C. A science research report D. A fashion journal
【小题1】C
【小题2】B
【小题3】A
【小题4】C
活力课时同步练习册系列答案
学业测评一课一测系列答案When prehistoric man arrived in new parts of the world, something strong happened to the large animals; they suddenly became extinct. Smaller species survived; the large, slow-growing animals were easy game, and were quickly hunted to extinction.
Now something similar could be happening in the oceans. That the seas are being over-fished has been known for years and researchers such as Ransom Myers and Boris Worm have shown how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) inanes fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.
Dr. Worm acknowledges that these figures are conservative (保守的). One reason for this is that fishing technology has improved. Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around noise.
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the date support an idea current among marine biologists, that of the “shifting baseline”. The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.
【小题1】The aim of the extinction of large prehistoric animals is to suggest that _______.
| A．large animal were not easy to survive in the changing environment |
| B．small species survived as large animals disappeared |
| C．large sea animals may face the same threat today. |
| D．Slow-growing fish outlive fast-growing ones |
| A．the stock of large predators in some old fisheries has reduced by 90% |
| B．there are only half as many fisheries are there were 15 years ago |
| C．the catch sizes in new fisheries are only 20% of the original amount |
| D．the number of larger predators dropped faster in new fisheries than in the old |
| A．fishing technology has improved rapidly |
| B．then catch-sizes are actually smaller then recorded |
| C．the marine biomass has suffered a greater loss |
| D．the date collected so far are out of date. |
| A．people should look for a baseline that can’t work for a longer time |
| B．fisheries should keep the yield below 50% of the biomass |
| C．the ocean biomass should restore its original level. |
| D．people should adjust the fishing baseline to changing situation. |
| A．management efficiency |
| B．biomass level |
| C．catch-size limits |
| D．technological application. |
XI'AN - China's conservation work for the endangered crested ibis（朱鹮）is facing new challenges, including an increasing mortality rate due to inbreeding, and the conflict between the need to expand natural habitats and local communities' economic interests, bird experts have warned.
The crested ibis, once widespread in Japan, China, Russia and the Korean Peninsula, almost 
became extinct in the first half of the 20th century.
Before 1981, when seven crested ibis were accidentally found in Yangxian county, in Northwest China's Shaanxi province, academics thought the species had been extinct in China for almost 17 years.
Due to the huge effort put into species protection since 1981, the number of crested ibis in China has risen to an estimated 1,617, including 997 in the wild, the State Forestry Administration said at a meeting on crested ibis protection in Xi'an on Monday.
However, although the ibis population exceeds 1,000, the birds are still not free from the threat of extinction, said Fang Shengguo, director of the State Conservation Center for Gene Resources of Endangered Wildlife at Zhejiang University.
“Ornithologists used inbreeding in the early stages of protection so that numbers of the precious birds could increase quickly, but that method had conseque
nces,” Fang said.
"Studies have proved that as a result of inbreeding, crested ibis have the lowest genetic diversity of all endangered birds," Fan
g said.
"It means a high mortality rate and more physical defects for hatched chicks."
“The government should collect genetic information from all crested ibis and establish a genetic database as soon as possible, then design a scientific mating plan for the species,” Fang said.
So far, about 90 percent of crested ibis live in Shaanxi province, and fewer than 140 ibis live in three zoos in other parts of the country, including Beijing Zoo, according to Liu Dongping, an assistant researcher at the National Bird Banding Center of China, which is affiliated to the Chinese 
Academy of Forestry.
The bird has lost the ability to migrate, he said, adding that if an unexpected natural disaster occurred in Shaanxi province or an infectious disease spread through the area, the ibis population could be greatly reduced.
Experts also warned that the increased population of ibis, whether in the wild or in captivity, requires a 
larger and more varied natural habitat.
Rampant hunting, the massive loss of habitat caused by deforestation and the overuse of pesticides, which killed aquatic insects on which the ibis feed, are believed to be the main reasons for the sharp reduction in the ibis population before 1981.
So, in 1983, a State-level natural reserve was set up in Shaanxi province to protect the bird. But the struggle for living space between human and animal has never stopped, said Lu Baozhong, deputy director of the Shaanxi Crested Ibis Conservation Station.
"For example, ibis often look for loaches in farmers' rice fields. Sometimes their claws trample the rice seedlings. In another case, villagers discovered some land with abundant mineral resources which happened to be a habitat for ibis," said Lu, who has devoted 30 years to ibis protection.
A long-term win-win solution for ibis and local communities needs to be developed, one that would provide ecological compensation for local residents, Lu said.
【小题1】. What’s the best title for the passage?
| A．The Rare Bird in China | B．New Problems for the Crested Ibis |
| C．The Way to Save the Crested Ibis | D．The Reason for the Crested Ibis’s Extinction |
| A．The crested ibis is a native of China. |
| B．Before 1981, the crested ibis was extinct in China. |
| C．The crested ibis is now free from the threat of extinction. |
| D．Most of the crested ibis are in Shaanxi province. |
is?| A．To increase the mortality rate. |
| B．To increase the number of the crested ibis. |
| C．To get more physical defects for hatched chicks |
| D．To have the lowest diversity of the endangered bird. |
| A．inbreeding | B．economic development |
| C．over hunting | D．sandstorm |
| A．Due to our great efforts, the crested ibis lives in the wild well. |
| B．Scientists will choose a better habitat for the crested ibis. |
C．The problems of the crested ibis have not been solved now. |
| D．The government has established a genetic database of the crested ibis. |