The Greatest Mystery of Whales The whale is a warm-blooded, air-breathing animal, giving birth to its young alive, sucking t

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问题                     The Greatest Mystery of Whales
    The whale is a warm-blooded, air-breathing animal, giving birth to its young alive, sucking them—and, like all mammals, originated on land. There are many 【C1】______of this. Its front flippers(鳍状肢), used for steering and stability, are traces of feet.
    Immense strength is【C2】______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 strength has been estimated 【C3】______ 400 horsepower. One specimen was reported to have towed(拖)a whaling vessel for seven hours at the 【C4】______of eight knot(节).
    An angry whale will 【C5】______. A famous example of this was the fate of Whaler Essex, 【C6】______was sunk off the coast of South America early in the last century. More recently, steel ships have【C7】______their plates buckled(使弯曲)in the same way. Sperm whales(抹香鲸)were known to seize the old-time whaleboats in their jaws and crush them.
    The greatest【C8】______of whales is their diving ability. The sperm whale dives to the bottom for his【C9】______food, the octopus(章鱼). In that search he is known to go as far down as 3 , 200 feet, where the【C10】______is 1 , 400 pounds, to a square inch. Doing so he will【C11】______underwater as long as one hour. Two special skills are involved in this storing up enough 【C12】______(all whales are air-breathed)and tolerating the great change in pressure. Just how he does it scientists have not【C13】______. It is believed that some of the oxygen is stored in a special 【C14】______of blood vessels, rather than just held in the lungs. And it is believed that a special kind of oil in his head is some sort of a compensating mechanism that【C15】______adjusts the internal pressure of his body. But since you can’t bring a live whale into the laboratory for study, no one knows just how these things work.
【C8】

选项 A、interest
B、job
C、danger
D、mystery

答案D

解析 本题所在句子为该段主题句,谈的是鲸鱼的潜水能力。鲸鱼的潜水能力很强,能下潜到很深的地方,科学家们不解,所以说是个谜,故选D。
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