Question

Blue whales are the largest animals ever known to have existed on the planet, and they can grow to a length of 100 feet and weigh more than 330,000 pounds.  But recently researchers have found that these whales are on the move and they have migrated from California waters to areas off Canada and Alaska for the first time since commercial whaling ended in 1965.

The researchers identified 15 blue whales that have appeared off the coast of British Columbia and the Gulf of Alaska since 1997. Four of these whales were recognized as ones that were once sighted off California shores, suggesting that the whales are returning to an old migration pattern between the coasts.

Before commercial whaling began in the early 1900s, blue whales were found widely throughout the North Pacific and California waters. But from the 1920s to the 1960s,whaling severely reduced the whale populations. Blue whales never recovered in the Northern Pacific, making sightings in this area rare.  However, much larger groups of whales have been observed close to California since the 1970s.

The scientists had previously thought that the California population was separate from the population that had historically lived in North Pacific waters. But the current study shows that whales off the coast of British Columbia and the Gulf of Alaska are likely part of the California population.

To identify the blue whales, the researchers looked at photos of cetaceans taken in the North Pacific Ocean and compared them with a library of blue whale pictures taken along the West Cost of the United States and Southern Pacific. Up to now, the researchers are not quite sure why the whales are changing their migration patterns, but they suspect that the whales may be following their food moving farther north by the changes in ocean conditions.

1.According to the passage, blue whales are          .

A. following a fixed route of migration

B.  dying out due to commercial whaling

C. moving from the south to the north

D. rarely found in the Southern Pacific

2.The whale population in the northern Pacific         .

A. is different from the California population

B. is probably part of the California population

C. has become the largest group since the 1970s

D. has lived there since the 1960s

3.The underlined word "cetaceans" in Paragraph 5 probably means          .

A. land creatures                       B. whale species

C. ocean conditions                     D. migration patterns

4.What might make blue whales migrate according to the researchers?

A. Commercial whaling.                   B. Weather conditions.

C. Life reproduction.                    D. Food resources.

Answer

1.C

2.B

3.B

4.D

【解析】

试题分析:本文主要讲述了科学家们对蓝鲸的研究，蓝鲸作为我们所熟知的最大的动物，近日正在由南向北迁移，并且研究人员已经在哥伦比亚海岸发现了蓝鲸的行踪。

1.】C 细节判断题。可根据第一段But recently researchers have found that these whales are on the move and they have migrated from California waters to areas off Canada and Alaska for the first time since commercial whaling ended in 1965.可知蓝鲸从美国向加拿大由南向北迁移，只有C选项是符合原文。

2.B 句意理解题。根据第四段目前的研究表明鲸鱼离开海岸到英国哥伦比亚海岸很有可能成为加利福尼亚鲸鱼总数的一部分。故选B.

3.B 词义猜测题。根据 To identify the blue whales, the researchers looked at photos of cetaceans taken in the North Pacific Ocean and compared them with a library of blue whale pictures taken along the West Cost of the United States and Southern Pacific.为了鉴别蓝鲸，研究人员仔细研究了所拍的照片。因此该词在此处的意思指的是鱼的种类。

4.

考点：考查说明类文章阅读。