The Greatest Mystery of Whales
The whale is a mammal (哺乳动物) --warm-blooded, air-breathing, giving birth to its young alive, sucking them--and, like all mammals, originated on land. There are many signs of this.
__________ (1) front flippers (鳍肢), used for steering and stability, are traces of feet.
Immense strength is built into the great body of the big whales, and in fact most of a whale's body is one gigantic muscle. The blue whale's pulling __________ (2) has been estimated at 400 horsepower. One specimen was reposed to have __________ (3) a whaling vessel for seven hours at the __________ (4) of eight knots.
An enraged whale will attack a ship. A famous__________(5) of this was the fate of whaler Essex, which was sunk__________(6) the coast of South America early in the last century. More recently, steel ships have had their plates buckled (扭曲变形) in the same way. Sperm whales were known to__________(7) the old-time whaleboats in their jaws and crush them.
The greatest mystery of whales is their diving ability. The sperm whale can __________(8) the bosom for his favorite food, the octopus (章鱼). __________(9) that search he is known to go as far down as 3,200 feet, where the pressure is 1,400 pounds to the square inch. Doing__________(10) he will remain submerged (水下的 ) as long as one hour. Two feats (绝技) are involved in this: storing up enough __________ (11) (all whales are air-breathed) and withstanding the great change in pressure. Just__________(12) he does it scientists have not determined. It is believed that some of the oxygen is stored in a special system of blood vessels, rather than just held in the lungs. And__________ (13) is believed that a special kind of oil in his head is some sort of compensating mechanism that automatically adjusts the internal pressure of his body. But __________(14) you can't bring a live whale into the laboratory for study, no one __________(15) just how these things work.
C. towed (拖)
6.A. offB. of C. aboveD. over
8.A. fly to
B. jump on
C. dive to
D. crawl on
10. A. so
D. the same
11. A. water
12. A. what
13. A. it
14. A. because of
B. due to
D. owing to
15. A. communicates
7.B。从上下文语境看，in their iaws这个短语决定了这里只可能用seize这个动词。鲸鱼把古代的捕鲸船咬在嘴里，然后把它咬碎。
12.c。本句是说，科学家只知道鲸鱼有储存氧气和抵御压力的绝技，但它究竟是怎么做到这一点的，他们却还不知道。注意这个句子里的宾语从句被移到前面来了。正常的语序是：Scientists have not determined how he does it.
13.A。这里用的是it is believed that…句型。it是形式主语，指代后面的that从句。这个that从句是一个主语从句。