共用题干The Greatest Mystery of WhalesThe whale i

共用题干

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______(51)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 wha’e’sbo衡is one gigantic muscle.The blue whale’s pulling strength has been estimated______(53) 400 horsepower.One specimen was reported to have towed（拖）a 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 Essex,______(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)underwater as long as one hour.Two special1 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______(64)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.

59._________ A:favorite B:fast C:new D:sufficient