B
Most polar bears could disappear by the end of the century because of global warming, scientists say.
According to a study in Nature Climate Change, the number of polar bears will fall quickly by 2080. One of the reasons is that the sea ice is melting(融化). Polar bears catch seals(海豹) to eat on the ice. Without ice, they have to stay on land. But there is not enough food on land to support so many polar bears. The animals could die from hunger. The other reason is that mother polar bears may not be fat enough to provide milk for their babies, so some bears stop having babies.
Polar bears are the largest land animals on the planet that eat meat. They help control other kinds of animals. Losing them would break the balance of their living place.
The Arctic Ocean(北冰洋) is the home of about 25,000 polar bears. Arctic sea ice usually melts in spring and summer, and then grows in winter. But now, the ice is taking longer to grow back. Scientists say the Arctic is warming twice as fast as the rest of the planet.
The study also shows that it is possible to slow Arctic ice melting. Greenhouse gases(温室气体) could lead to climate change. In order to stop creating greenhouse gases, the world should try to give up burning coal(煤炭) and riding in cars.
Saving the bears is meaningful to us. Holland, one of the writers of the study, says, "I believe there is hope, but humans need to act quickly to make that hope come true." Let's take action to save polar bears.
() 4. How many reasons are mentioned to show why polar bears are in danger?
A. One.
B. Two.
C. Three.
D. Four.
() 5. According to the passage, the climate change makes Arctic sea ice .
A. stop growing back in winter
B. keep melting both in spring and winter
C. melt twice faster than the rest of the planet
D. take more time to grow back to ice in winter
() 6. What is the main purpose of this passage?
A. To show the importance of ice.
B. To make people like polar bears.
C. To ask people to protect polar bears.
D. To explain natural climate change.
Most polar bears could disappear by the end of the century because of global warming, scientists say.
According to a study in Nature Climate Change, the number of polar bears will fall quickly by 2080. One of the reasons is that the sea ice is melting(融化). Polar bears catch seals(海豹) to eat on the ice. Without ice, they have to stay on land. But there is not enough food on land to support so many polar bears. The animals could die from hunger. The other reason is that mother polar bears may not be fat enough to provide milk for their babies, so some bears stop having babies.
Polar bears are the largest land animals on the planet that eat meat. They help control other kinds of animals. Losing them would break the balance of their living place.
The Arctic Ocean(北冰洋) is the home of about 25,000 polar bears. Arctic sea ice usually melts in spring and summer, and then grows in winter. But now, the ice is taking longer to grow back. Scientists say the Arctic is warming twice as fast as the rest of the planet.
The study also shows that it is possible to slow Arctic ice melting. Greenhouse gases(温室气体) could lead to climate change. In order to stop creating greenhouse gases, the world should try to give up burning coal(煤炭) and riding in cars.
Saving the bears is meaningful to us. Holland, one of the writers of the study, says, "I believe there is hope, but humans need to act quickly to make that hope come true." Let's take action to save polar bears.
() 4. How many reasons are mentioned to show why polar bears are in danger?
A. One.
B. Two.
C. Three.
D. Four.
() 5. According to the passage, the climate change makes Arctic sea ice .
A. stop growing back in winter
B. keep melting both in spring and winter
C. melt twice faster than the rest of the planet
D. take more time to grow back to ice in winter
() 6. What is the main purpose of this passage?
A. To show the importance of ice.
B. To make people like polar bears.
C. To ask people to protect polar bears.
D. To explain natural climate change.
答案：4. B 5. D 6. C
解析：
4. 文章第二段明确指出了北极熊陷入危机的两个原因：一是海冰融化后北极熊只能留在陆地，陆地上没有足够的食物，它们可能会饿死；二是北极熊妈妈无法积累足够的脂肪为幼崽哺乳，部分北极熊停止繁育后代，因此一共提到了2个相关原因。
5. 根据文章第四段内容“Arctic sea ice usually melts in spring and summer, and then grows in winter. But now, the ice is taking longer to grow back.”可知，气候变化让北极海冰在冬季重新凝结变回冰需要花费更长时间，和D选项描述一致。
6. 全文介绍了北极熊因全球变暖濒临消失的现状、濒危的原因以及保护北极熊的意义，最后发出呼吁号召大家行动起来拯救北极熊，因此文章的主要目的是呼吁人们保护北极熊。
5. 根据文章第四段内容“Arctic sea ice usually melts in spring and summer, and then grows in winter. But now, the ice is taking longer to grow back.”可知，气候变化让北极海冰在冬季重新凝结变回冰需要花费更长时间，和D选项描述一致。
6. 全文介绍了北极熊因全球变暖濒临消失的现状、濒危的原因以及保护北极熊的意义，最后发出呼吁号召大家行动起来拯救北极熊，因此文章的主要目的是呼吁人们保护北极熊。