D
Scientists think they have answered a mystery：How some ocean creatures got so huge so quickly.
A few million years ago, the largest whales，averaged about 15 feet long.Then seemingly overnight, one type of whale, the toothless baleen whale (须鲸类) became huge.Modern blue whales get as big as 100 feet. Nicholas Pyenson of the Smithsonian Natural History Museum said，“Why is that？”“It happened in the glance of an evolutionary eye, which makes it harder to figure out what happened，” said Graham Slater，lead author of the study. Their study has suggested an answer：Ice ages in the last 3 to 5 million years started it, changing the oceans and food supply for whales.
The researchers used fossil records of the smaller whales to create a family tree for baleen whales which include blue whales, humpbacks and right whales. Using computer simulations (模拟) and knowledge about how evolution works，they concluded that when the size changes started, the poles got colder, ice expanded and the water circulation in the oceans changed and winds shifted.Slater and Pyenson said cold water went deep and moved closer to the equator (赤道) and then eventually moved back up with small fish and other small animals that whales eat.
Baleen whales, which have no teeth, feed by eating huge amounts of fish they capture.Toothed whales, like sperm whales (抹香鲸), hunt individual fish, so the ocean changes that made food less evenly spread out didn't affect them as much. But baleen whales hunt schools of fish.
Olivier Lambert at the Royal Belgian Institute of Natural Sciences calls it “a really convincing situation”．But he said the lack of fossils in certain time periods is an issue.As oceans warm from manmade climate change，the seas will be more like it was when the whales were smaller and they will have a more difficult time surviving.
【语篇解读】 文章以鲸鱼为例分析了一些海洋动物快速变大的原因，提出了气候变化引起海洋变化，造成鲸鱼生存困难的现状，呼吁人们保护环境和动物。
12．What does the author mean by “It happened in the glance of an evolutionary eye” in the second paragraph?
A．The change of baleen whales happened too quickly.
B．The change of baleen whales was too difficult to explore.
C．Researchers paid little attention to the change of baleen whales.
D．Researchers thought the change of baleen whales was unimportant.
A [句意理解题。根据下句“which makes it harder to figure out what happened”可知画线句子指这种变化在进化的发展中只是匆匆一瞥，形容其速度之快。A项正好表达了此意。]
13．What played the key role in baleen whales' becoming huge?
A．Manmade climate change.
B．Its eating a huge amount of fish.
C．The water circulation in the oceans.
D．The increase of food supply for whales.
D [推理判断题。根据第二段最后一句、第三段最后一句和第四段中“But baleen whales hunt schools of fish.”可知由于海水流向和鲸鱼食物来源的变化，须鲸能捕获到鱼群，食物增多，体积变大。故选D。]
14．What do we know about sperm whales and blue whales according to the text?
A．Sperm whales eat more food.
B．Blue whales live much longer.
C．Sperm whales prefer to hunt schools of fish.
D．Blue whales usually swallow schools of fish.
D [推理判断题。根据第二段中“the toothless baleen whale(须鲸类)became huge.Modern blue whales get as big as 100 feet.”和第四段中“Toothed whales，like sperm whales(抹香鲸)，hunt individual fish...But baleen whales hunt schools of fish.”可知sperm whales和blue whales的情况，blue whales属于baleen whales，能捕获鱼群。故选D。]
15．What can we infer from the last paragraph?
A．There are no whale fossils now.
B．The whales may become even bigger.
C．Global warming has threatened the whales.
D．Olivier Lamber thinks the study is perfect.
C [推理判断题。根据最后一段最后一句可知由于气候变暖引起海洋变化，威胁鲸鱼的生存。故选C。]
Scientists think they have answered a mystery：How some ocean creatures got so huge so quickly.
A few million years ago, the largest whales，averaged about 15 feet long.Then seemingly overnight, one type of whale, the toothless baleen whale (须鲸类) became huge.Modern blue whales get as big as 100 feet. Nicholas Pyenson of the Smithsonian Natural History Museum said，“Why is that？”“It happened in the glance of an evolutionary eye, which makes it harder to figure out what happened，” said Graham Slater，lead author of the study. Their study has suggested an answer：Ice ages in the last 3 to 5 million years started it, changing the oceans and food supply for whales.
The researchers used fossil records of the smaller whales to create a family tree for baleen whales which include blue whales, humpbacks and right whales. Using computer simulations (模拟) and knowledge about how evolution works，they concluded that when the size changes started, the poles got colder, ice expanded and the water circulation in the oceans changed and winds shifted.Slater and Pyenson said cold water went deep and moved closer to the equator (赤道) and then eventually moved back up with small fish and other small animals that whales eat.
Baleen whales, which have no teeth, feed by eating huge amounts of fish they capture.Toothed whales, like sperm whales (抹香鲸), hunt individual fish, so the ocean changes that made food less evenly spread out didn't affect them as much. But baleen whales hunt schools of fish.
Olivier Lambert at the Royal Belgian Institute of Natural Sciences calls it “a really convincing situation”．But he said the lack of fossils in certain time periods is an issue.As oceans warm from manmade climate change，the seas will be more like it was when the whales were smaller and they will have a more difficult time surviving.
【语篇解读】 文章以鲸鱼为例分析了一些海洋动物快速变大的原因，提出了气候变化引起海洋变化，造成鲸鱼生存困难的现状，呼吁人们保护环境和动物。
12．What does the author mean by “It happened in the glance of an evolutionary eye” in the second paragraph?
A．The change of baleen whales happened too quickly.
B．The change of baleen whales was too difficult to explore.
C．Researchers paid little attention to the change of baleen whales.
D．Researchers thought the change of baleen whales was unimportant.
A [句意理解题。根据下句“which makes it harder to figure out what happened”可知画线句子指这种变化在进化的发展中只是匆匆一瞥，形容其速度之快。A项正好表达了此意。]
13．What played the key role in baleen whales' becoming huge?
A．Manmade climate change.
B．Its eating a huge amount of fish.
C．The water circulation in the oceans.
D．The increase of food supply for whales.
D [推理判断题。根据第二段最后一句、第三段最后一句和第四段中“But baleen whales hunt schools of fish.”可知由于海水流向和鲸鱼食物来源的变化，须鲸能捕获到鱼群，食物增多，体积变大。故选D。]
14．What do we know about sperm whales and blue whales according to the text?
A．Sperm whales eat more food.
B．Blue whales live much longer.
C．Sperm whales prefer to hunt schools of fish.
D．Blue whales usually swallow schools of fish.
D [推理判断题。根据第二段中“the toothless baleen whale(须鲸类)became huge.Modern blue whales get as big as 100 feet.”和第四段中“Toothed whales，like sperm whales(抹香鲸)，hunt individual fish...But baleen whales hunt schools of fish.”可知sperm whales和blue whales的情况，blue whales属于baleen whales，能捕获鱼群。故选D。]
15．What can we infer from the last paragraph?
A．There are no whale fossils now.
B．The whales may become even bigger.
C．Global warming has threatened the whales.
D．Olivier Lamber thinks the study is perfect.
C [推理判断题。根据最后一段最后一句可知由于气候变暖引起海洋变化，威胁鲸鱼的生存。故选C。]
