题目内容
Antarctic _____ we know very little is covered with thick ice all the year round.
A. which B. that C. where D. about which
D
Antarctic seabirds are breeding（繁殖）later, because thinner sea ice is causing their food supplies to decline, a new study says. The birds, which nest in East Antarctica, have delayed their spring arrival by an average of nine days and egg-laying by an average of two days over the past 50 years, according to polar researchers from the French National Center for Scientific Research in Villiers en Bois, France, study authors Christophe Barbrand and Henri Weimerskirch attribute this later breeding activity to decreases in sea ice caused by climate change. The emperor penguin is the tallest and heaviest of all living penguin species and lives in Antarctica. The male and female are similar in size, reaching 122 cm in heig
ht and weighing anywhere from 22 to 45 kg. The back and head are black, contrasting sharply with the pale-yellow breast and bright-yellow ears. Like all penguins, it is flightless, with a streamlined body and their wings stiffen and flatten into flippers(鳍状肢) for a marine habitat.
Its diet consists primarily of fish, but can also include animals with hard shells. In hunting, the species can remain underwater up to 18 minutes, diving to a depth of 535 m. Its unusually structured hemoglobin(血红蛋白)a
llows it to function at low oxygen levels.
The emperor penguin is perhaps best known for the journeys adults make each year in order to mate and to feed their babies. The only penguin species that breeds(繁殖) during the Antarctic winter, it goes on a long journey of 50-120 km over the ice to breeding areas which may include thousands of individuals. The female lays a single egg, which is incubated(孵化)by the male while the female returns to the sea to feed; parents take turns searching for food at sea and caring for their chick. They both care for the chick until it is able to enter the water to find food on its own. During the process of incubation, the male can lose up to 1/3 to 1/2 of his body weight. One of the coolest things about the male is that if the chick comes out its egg before the female returns, the male can actually produce a special liquid to feed the chick. He can only do this for a short time. If the female doesn’t return, he must leave the chick to go on with his own life. The emperor penguin can typically live for 20 years in the wild, although observat
ions suggest that some individual may live to 50 years of age.
【小题1】We can learn from paragraph 1 that ____.
| A．the emperor penguin is the world’s largest kind of penguin |
| B．the emperor penguin has pale-yellow ears |
| C．the male and female emperor penguins are of different sizes |
| D．the emperor penguin lives in the most northern area on the Earth |
| A．strong wings | B．streamlined body | C．structured hemoglobin | D．special diet |
om other penguin species in that ____.| A．it gives birth in the Antarctic winter | B．it feeds mainly on fish |
| C．the male won’t search for food on his own | D．it can only live for a short time |
| A．the egg of the emperor penguin is mainly incubated by the female |
| B．many emperor penguins will stay together to breed |
| C．the male emperor penguin will give up his own life to feed the chick |
| D．the female emperor penguin will leave the chick forever once it lays an egg |
Far from the land of Antarctica (南极洲), a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.
For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer. Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish’s blood and measured its freezing point. The fish were taken from seawater that had a temperature of -1.88°C and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to -2.05°C. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.
The scientists’ next research job was clear: Find out what in the fish’s blood kept it from freezing. Their search led to some really strange thing made up of a protein (蛋白质) never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.
Study showed that it is an unusual kind of protein. It has many small sugar molecules held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein, or AFGP.
【小题1】 What is the text mainly about?
| A．The terrible conditions in the Antarctic. | B．A special fish living in freezing waters. |
| C．The ice shelf around Antarctica. | D．Protection of the Antarctic cod. |
A. The seawater has a temperature of -1.88°C. B. it loves to live in the ice-salt mixture
C. A special protein keeps it from freezing.
D. Its blood has a temperature lower than -2.05°C.
【小题3】What does the underlined word “it” in Paragraph 5 refer to?
| A．A type of ice-salt mixture. | B．A newly found protein. |
| C．Fish blood. | D．Sugar molecule. |
| A．sugar | B．ice | C．blood | D．molecule |
, cetaceans that rely on polar, icy waters for their home and food resources are likely to be greatly affected by the reduction of sea ice cover.
. From the passage, we can learn that whales mainly feed on ______.