Question

Around 200 million years ago, the earth was 18 degrees warmer than it is now. That might be a bit hot for humans, but it was just right for the giant dinosaurs that wandered about the earth during the Mesozoic (中生代的) era. A new study found that planteating dinosaurs may have contributed to the warming of the earth?by releasing significant amounts of methane (甲烷)．

The study, published in science journal Current Biology, focused on sauropods, long?necked herbivores (食草動物) that munched (用力咀嚼) on the top of trees. They were the largest of the dinosaurs; food broke down in their stomachs for long periods of time. The researchers estimate that a sauropoda released 2,675 liters of methane per day—adding up to a large amount of the greenhouse gas being pumped from dinosaur's gut into the atmosphere.

Plant eaters naturally release methane as part of their digestive process. The larger the animal, the more methane it produces. Methane, a greenhouse gas, traps heat and remains in the atmosphere for approximately 9?15 years, which warms the atmosphere.

Today, some animals, such as cattle, goats and sheep, produce large amounts of methane as a by?product to their food digestion. Methane is also released from human—influenced sources such as landfill, agricultural activities, coal mining and other industrial practices—which all contribute to today's climate change, according to the Environmental Protection Agency.

The researchers estimate that earth's sauropods would have produced about 520 million tons of methane per year—similar to the total amount of methane produced today by natural and man?made sources. However, the researchers warn that their numbers are estimates based on multiple assumptions about the digestive systems and populations of dinosaurs.

The author of the study David Wilkinson says the emission of methane from dinosaurs would have been just one of the causes of warm climate during the Mesozoic era. Other causes include gases produced from volcanoes, swamps, shallow seas and so on. Still, Wilkinson says，“ The amount of methane from dinosaurs is large enough to have a measurable effect.”

1.Scientists think dinosaurs may have led to the global warming because ________.

A．they ate everything they found

B．they usually had a good appetite

C．they released a lot of methane

D. there were too many dinosaurs on earth

2.What do we know about dinosaurs from Paragraph 2?

A．Sauropods fed on plants.

B．Sauropods were of medium size.

C．Dinosaurs used to live on trees.

D．Dinosaurs digested food quickly.

3.Which of the following activities doesn't produce methane?

A．Coal is dug out by machine.

B．Trees and flowers are planted.

C．Goats digest grass under the tree.

D．Food is being processed in the factory.

4.How does the author make his writing reliable?

A．By listing some facts.

B．By making predictions.

C．By citing figures.

D．By using mind pictures.

5.David Wilkinson seems to believe that ________.

A．methane had little effects on the earth

B．many other factors contributed to warm climate

C．other causes for warm climate were worth considering

D．dinosaurs were mainly to blame for global warming

 

Answer 1

1.C

2.A

3.B

4.C

5.B

【解析】

文章大意：一項研究發(fā)現(xiàn)，中生代全球變暖很可能是因為恐龍釋放出了大量的甲烷。

1.答案：C　細(xì)節(jié)理解題。根據(jù)第一段的最后一句可知，恐龍導(dǎo)致全球變暖是因為它們釋放出了大量的甲烷。

2.2】答案：A　細(xì)節(jié)理解題。根據(jù)第二段的內(nèi)容可知，蜥腳類恐龍是長脖子食草動物，體形碩大。故A項正確。

3.3】答案：B　細(xì)節(jié)理解題。根據(jù)第四段可知，動物消化食物時，會釋放出甲烷。而且，在廢物填埋、農(nóng)業(yè)活動、煤礦開采以及其他工業(yè)生產(chǎn)過程中，都會產(chǎn)生甲烷。因此B項符合題意。

4.4】答案：C　推理判斷題。作者在文中多次引用數(shù)字，以提高文章內(nèi)容的可信度。

5.5】答案：B　推理判斷題。根據(jù)最后一段的內(nèi)容可知，David Wilkinson認(rèn)為除了恐龍排放的甲烷之外，還有其他一些因素導(dǎo)致全球變暖。