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℃ 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℃. 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(分子) 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.
68. 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.
69. Why can the Antarctic cod live at the freezing temperature?
A. The seawater has a temperature of -1.88℃.
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℃.
70. 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.
71. What does “glycol-” in the underlined word “glycoprotein” in the last paragraph mean?
A. sugar B. ice C. blood D. molecule
Cold weather can be hard on pets, just like it can be hard on people. Sometimes owners forget that their pets are just as used to the warm shelter (住所) as they are. Some owners will leave their animals outside for a long period of time, thinking that all animals are used to living outdoors. This can put their pets in danger of serious illness. There are things you can do to keep your animal warm and safe....What do we learn about pets from Paragraph 1?
| A．They are often forgotten by their owners. |
| B．They are used to living outdoors. |
| C．They build their own shelters. |
| D．They like to stay in warm places. |
With a PhD in Mathematics Education from Georgia State University, Dr. Siegel teaches mathematics at Central Arizona College. His courses include various makeup classes and a number of lectures for future primary school teachers.
If the course fails to provide complete satisfaction to you, you can easily exchange it for any other course that we offer. Or you can get your money back.Where is the passage most likely to have been taken from?
| A．A news report. |
| B．A book review. |
| C．A lesson plan. |
| D．An advertisement. |
The honey guide does not actually like honey, but it does like the wax in the beehives (蜂房). The little bird cannot reach this wax, which is deep inside the bees' nest. So, when it findsa suitable nest, it looks for someone to help it. The honey guide gives a loud cry that attracts the attention of both passing animals and people. Once it has their attention, it flies through the forest, waiting from time to time for the curious animal or person as it leads them to the nest. When they finally arrive at the nest, the_follower reaches in to get at the delicious honey as the bird patiently waits and watches. Some of the honey, and the wax, always falls to the ground, and this is when the honey guide takes its share.What do the words “the follower” in Paragraph 2 refer to?
| A．A bee. | B．A bird. |
| C．A honey seeker. | D．A beekeeper. |
Keep your pets inside as much as you can when the weather is bad. If you have to take them out, stay outside with them. When you're cold enough to go inside, they probably are too. If you must leave them outside for a long time, make sure they have a warm, solid shelter against the wind, thick bedding, and plenty of nonfrozen water....Why are pet owners asked to stay with their pets when they are out in cold weather?
| A．To know when to bring them inside. |
| B．To keep them from eating bad food. |
| C．To help them find shelters. |
| D．To keep them company. |
Facial expressions carry meaning that is determined by situations and relationships. For example, in American culture (文化) the smile is in general an expression of pleasure. Yet it also has other uses. A woman's smile at a police officer does not carry the same meaning as the smile she gives to a young child.A smile may show love or politeness.It can also hide feelings.It often causes confusion(困惑) across cultures. For example, many people in Russia consider smiling at strangers in public to be unusual and even improper. Yet many Americans smile freely at strangers in public places (although this is less common in big cities). Some Russians believe that Americans smile in the wrong places; some Americans believe that Russians don't smile enough. In Southeast Asian cultures, a smile is frequently used to cover painful feelings. Vietnamese people may tell a sad story but end the story with a smile...What would be the best title for the text?
| A．Cultural Differences |
| B．Smiles and Relationships |
| C．Facial Expressiveness |
| D．Habits and Emotions |