The Greatest Mystery of Whales
% l; {4 h! m! |! Q4 m$ YThe whale is a mammal - 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, used for steering and stability, are traces of feet.. w( k" k4 x. \3 T* u9 i) Z9 D
Immense strength is built 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 __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.
H( I# c/ g0 o. N% mAn 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.
: w4 s( S( ?4 w: ]8 k" _The greatest mystery of whales is their diving ability. The sperm whale __8__ the bottom for his favourite 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 dose 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 can't bring a live whale into the laboratory for study, no one __15__ just how these things work.% s4 s/ p4 x* X" b
EXERCISE:9 S0 e+ \- q' U. I! v
1. A)Their B)His C)Theirs D)Its/ `) }' Q4 o8 E! u
2. A)strength B)width C)height D)length9 z- X) q6 s! h, O
3. A)eaten B)crashed C)towed D)lifted
. b9 x8 {+ b1 C6 u# O$ O4. A)distance B)rate C)voyage D)sail: x5 a+ q+ S$ n4 }3 Z' J7 {
5. A)picture B)film C)example D)book
; S: B% F3 \1 S" z6. A)off the coast of B)of the coast of C0away the coast of D)in the coast of5 n! W6 v! @% A$ p9 `
7. A)hit B)seize C)damage D)overturn
* m2 ]* W! W, J1 d. g; ]8. A)sink to B)rest on C)dive to D)hide on; ~/ r+ W! m; U
9. A)In that search B)Because of this C)In spite of that D)In support of this- ]: i8 n* Y4 L1 d; ]( W
10. A)so B)such C)above D)the same
* K% y% `4 K; H* g0 e$ m. a11. A)air B)oxygen C)energy D)heat# G6 m- v, h3 ~& y$ c: ~
12. A)what B)where C)how D)when0 x& @6 g6 R W: l. M
13. A)it is believed B)he believes C)we believe D)it believes
/ v* D- `9 K& J8 C$ q14. A)because of B)due to C)since D)owing to
7 \6 n% [, ^1 H0 j& S15. A)communicates B)knows C)hears D)develops
; a- a# N1 W/ _2 gKEY:D A C B C A B C A A B C A C B |