阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案，并涂在答题卡相应的位置上。 The Greatest Mystery of Whales （鲸鱼）
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（鳍状肢）, 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 whales body is one gigantic（强有力的） muscle. The blue whales pulling 2 has been estimated at 400 horsepower. One specimen was reported 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 South America early in the last century. More recently, steel ships have had their plates buckled 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 8 the bottom for his favorite food, the octopus. 9 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 as long as one hour. Two feats 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 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 cant bring a live whale into the laboratory for study, no one just 15 how these things work.
1. A) Its B) His C) Theirs D) Their 2. A) width B) strength C) height D) length 3. A) eaten B) crashed C) lifted D) towed 4. A) distance B) voyage C) rate D) sail 5. A) picture B) example C) film D) book 6. A) away the coast of B) of the coast of C) off the coast of D) in the coast of 7. A) seize B) hit C) damage D) overturn 8. A) sink to B) dive to C) rest on D) hide on 9. A) In spite of that B) Because of this C) In that search D) In support of this 10.A) the same B) such C) above D) so 11. A) oxygen B) air C) energy D) heat 12.A) what B) where C) how D) when 13.A) it is believed B) it believes C) we believe D) he believes 14.A) because of B) due to C) owing to D) since 15.A) communicates B) hears C) knows D) develops