共用题干 The Greatest Mystery of Wha1egThe whale is a warm一blooded,air-breathing animal,giving birth to its young alive,ing them一and, like all mammals,originated on land. There are many__________of this. Its front flippers (鳍状肢), used for steering and stability,are traces of feet.Immense strength is________(52)into the great body of the big whales,and in fact most of a whale',body is one gigantic muscle.The blue whale'S pulling strength has been estimated________.(53) 400 horsepower. One specimen was reported to have towed(拖)。whaling vessel for seven hours at the _______(54)of eight knot(节).An angry whale will________(55).A famous example of this was the fate of Whaler Es, ________(56)was sunk off the coast of South America early in the last century.More recently,steel ships have_(57)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________(58)of whales is their diving ability.The sperm whale dives to the bottom for his________(59)food,the octopus(章鱼),In that search he is known to go as far down as 3 , 200 feet,where the________(60)is 1,400 pounds,to a square inch.Doing so he will________(61)underwa- ter as long as one hour. Two special skills are involved in this storing up enough________(62)(all whales are air-breathed)and tolerating the great change in pressure.Just how he does it scientists have not _________(63).It is believed that some of the oxygen is stored in a special________()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_________(65)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. _________