The Greatest Mystery of Whales# {' }7 e+ r! ]/ U
The 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.' r- V* m/ G6 N! U( @1 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.6 y! L7 U8 d. P
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.) m b+ ~* J( G4 e: v
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.
" E1 R; P5 S5 W* tEXERCISE:7 A4 B0 K1 g, L) J j
1. A)Their B)His C)Theirs D)Its3 b F' w9 U# w7 m6 b% P
2. A)strength B)width C)height D)length( G% I0 ^; T7 H$ |
3. A)eaten B)crashed C)towed D)lifted
$ Y- h+ y1 y5 O0 W( s2 V4. A)distance B)rate C)voyage D)sail! o) i" X- T. W9 I7 J6 ~/ N, f P. y
5. A)picture B)film C)example D)book
( A0 O. }, q3 A1 D6. A)off the coast of B)of the coast of C0away the coast of D)in the coast of
2 j: q4 y# X1 K7. A)hit B)seize C)damage D)overturn, M" d0 `5 c1 f& r' _: W5 H
8. A)sink to B)rest on C)dive to D)hide on
9 ?: T/ Q1 X2 l: G* K9. A)In that search B)Because of this C)In spite of that D)In support of this
7 ^' ^1 m" D1 W$ t1 l U10. A)so B)such C)above D)the same
! W% v$ K7 V! J11. A)air B)oxygen C)energy D)heat
7 x. G" P& f& ~6 S12. A)what B)where C)how D)when
3 y' `2 A# I4 o7 L$ k! q" o/ D$ H13. A)it is believed B)he believes C)we believe D)it believes6 r6 i0 H! U+ z; w
14. A)because of B)due to C)since D)owing to
7 B, \3 O/ v- t5 y) M+ S4 \2 B' F( l15. A)communicates B)knows C)hears D)develops% W$ Q# r5 B" K0 Y
KEY:D A C B C A B C A A B C A C B |
发表于 2012-8-15 23:30:26
