根据下列材料，回答51-65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 front flippers(鳍状肢), used for steering and stability, are traces of feet. (51) of this. Its Immense strength is (52) 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 (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 crash 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 3200 feet，where the． (60) is l400 pounds，to a square inch．Doing so he will (61) underwater long as one hour．Two special skills are involved in this storing up enough (62) (all whales ale 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 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．
A．aspects
B．signs
C．ways
D．reasons
52、
A．worked
B．divided
C．built
D．moved
53、
A．al
B．in
C．of
D．with
54、
A．number
B．degree
C．distance
D．rate
55、
A．abandon
B．attack
C．leave
D．board
56、
A．as
B．who
C．which
D．that
57、
A．had
B．operated
C．Seen
D．caught
58、
A．interest
B．job
C．danger
D．mystery
59、
A．favorite
B．fast
C．new
D．sufficient
60、
A．depth
B．pressure
C．level
D．size
61、
A．set
B．become
C．remain
D．rest．
62、
A．heat
B．energy
C．food
D．oxygen
63、
A．witnessed
B．determined
C．applied
D．calculated
64、
A．system
B．place
C．arrangement
D．equipment
65、
A．mentally
B．artificially
C．manually
D．automatically