�4. When she was a child, Linda her mother her a story. A) was always worrying, telling C) always worried, telling C) was always worrying, to tell D) always worried, to tell 题目和参考答案——青夏教育精英家教网—

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�4. When she was a child, Linda ________ her mother ________ her a story.

A) was always worrying, telling C) always worried, telling

C) was always worrying, to tell D) always worried, to tell

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Ocean Acidification: 'Evil Twin' Threatens World's Oceans
The rise in human emissions of carbon dioxide is driving dangerous changes in the chemistry and ecosystems of the world's oceans, international marine（海洋的）scientists have warned. "Ocean conditions are already more extreme than those experienced by marine organisms and ecosystems for millions of years," says the latest issue of the journal Trends in Ecology and Evolution. "This emphasizes the urgent need to adopt policies that markedly reduce CO2 emissions."
Ocean acidification, which the researchers call the 'evil twin of global warming', is caused when the CO2 emitted by human activity, mainly burning fossil fuels, dissolves into the oceans. It is happening independently of, but in combination with, global warming. Evidence gathered by scientists over the last few years suggests that ocean acidification could represent an equal -- or perhaps even greater threat -- to the biology of our planet than global warming. More than 30% of the CO2 released from burning fossil fuels, cement production, deforestation and other human activities goes straight into the oceans, turning them gradually more acidic.
"The resulting acidification will impact many forms of sea life, especially organisms whose shells or skeletons are made from calcium carbonate（碳化钙）, like corals and shellfish. It may interfere with the reproduction of plankton species which are a vital part of the food web on which fish and all other sea life depend," he adds.
The scientists say there is now persuasive evidence that mass extinctions in past Earth history, like the "Great Dying" of 251 million years ago and another wipeout 55 million years ago, were accompanied by ocean acidification, which may have delivered the deathblow to many species that were unable to cope with it. "These past periods can serve as great lessons of what we can expect in the future, if we continue to push the acidity the ocean even further" said lead author, Dr. Carles Pelejero, from ICREA and the Marine Science Institute of CSIC in Barcelona, Spain. "Given the impacts we see in the fossil record, there is no question about the need to immediately reduce the rate at which we are emitting carbon dioxide in the atmosphere," he said further.
"Today, the surface waters of the oceans have already acidified by an average of 0.1 pH units from pre-industrial levels, and we are seeing signs of its impact even in the deep oceans," said co-author Dr. Eva Calvo, from the Marine Science Institute of CSIC in Spain. "Future acidification depends on how much CO2 humans emit from here on -- but by the year 2100 various projections indicate that the oceans will have acidified by a further 0.3 to 0.4 pH units, which is more than many organisms like corals can stand," Prof. Hoegh-Guldberg says.
"This will create conditions not seen on Earth for at least 40 million years."
"These changes are taking place at rates as much as 100 times faster than they ever have over the last tens of millions of years" Prof. Hoegh-Guldberg says. Besides directly impacting on the fishing industry and its contribution to the human food supply at a time when global food demand is doubling, a major die-off in the oceans would affect birds and many land species and change the biology of Earth as a whole profoundly, Prof. Hoegh-Guldberg adds.
67. What is the biggest cause of the ocean acidification according to the report?
A. the increase of carbon dioxide emission by human beings
B. The worsening of global warming
C. The disappearance of the world’s forests
D. The decrease of marine life
68. In what way according to the report does ocean acidification affect the majority of marine life?
A. It affects their reproduction          B. It destroys their food chain
C. It affects the growth of their young    D. destroys their habitats
69. Which of the following statements is NOT true about ocean acidification?
A. Ocean acidification has made ocean conditions most extreme in millions of years.
B. Ocean acidification may do more damage than global warming to human and plant life in the long run.
C. Ocean acidification is suspected of having caused mass extinctions of life in past Earth history.
D. The effects of ocean acidification are not now but will be felt in the foreseeable future.
70. From the report we can clearly feel that the situation with ocean acidification __________.
A. is quite optimistic                B. remains well under control
C. looks more than urgent            D. is already out of control

If you are looking for an animal to take the title of “most violent fish in the sea”, then the tiger puffer (河豚) fish would have to be a strong contestant. Not only is it deadly poisonous --- though that doesn’t stop people trying to eat it --- but it is also able to scare off enemies by inflating itself to become much larger than normal, when it is young it even chews on its own brothers and sisters.
Tiger puffer fish attach their eggs to rocks near the bottom of the sea, often at the mouths of bays. Then the larvae (幼鱼) move to the entries of rivers and lakes once they have grown a little. Then, having put on a lot of weight, they head out to sea. There’s no innocent childhood for the puffer fish, as Shin Oikawa of Kyushu University in Japan and his colleagues found out when they put the larvae of tiger puffer fish in the lab and monitored them for two months. They found that the larvae went through three steps in which their metabolic(新陈代谢) rates increased dramatically when they reached body weights of 0.002g, 0.01g, and 0.1g. When a larva went through one of these steps, its behavior also changed. For instance, once a larva had passed the first level it would have grown its first tooth and could start attacking larvae that had not yet reached that stage. Similarly, any larva that had reached the 0.01g or 0.1g levels would start attacking lighter larvae.
The researchers noted that the baby fish had a “relatively small mouth”, so rather than swallowing their brothers and sisters whole, they would bite pieces out of them. Despite this limitation, the fish caused plenty of deaths --- up to 12 per cent of the deaths that happened in the lab each day.
Those fish that grew fast enough to be able to chew on their fellows had an advantage. The extra food accelerated their growth and development. Tiger puffer fish are likely to be faster and swifter, so they can deal better with enemies.
As the name suggests, puffer fish can inflate to make themselves seem much larger than they really are, thus scaring off enemies. They do this by filling their stomachs, which are extremely elastic(弹性的), with water. If that’s not enough of a threat, the tiger puffer fish --- like most of the other puffer fish in the family --- carries a deadly toxin(毒素). Eat one puffer fish and the poison will paralyze (瘫痪) your muscles, including the muscles responsible for breathing, so death is usually caused by a lack of oxygen. Famously, the fish is a delicacy in Japan, where highly qualified chefs produce dishes that contain the safe level of the poison. Interestingly, the puffer fish does not go to the trouble of producing the poison itself. Instead, it hosts bacteria (细菌) that produce the stuff. It obtains these bacteria from its diet, so the youngest adult fish are not poisonous.
【小题1】All of the following statements account for the violence of puffer fish except that_____.

A．they are very difficult to catch

B．they can become larger to threaten enemies away

C．they kill their younger companions as they grow up

D．they are deadly poisonous

【小题2】We can learn from the second paragraph that puffer fish _____.

A．can only grow to a weight of 0.1g

B．do not change their behavior as they grow up

C．like to find a safe place to hatch the next generation

D．begin to grow teeth when they reach the third level

【小题3】Where does the poison in the puffer fish’s body come from?