时间:2018-12-30 作者:英语课 分类:托福听力短文


英语课
(woman) To us, the environment in which fish dwell often seems cold, dark, and mysterious. But there are advantages to living in water, and they have played an important role in making fish what they are. One is that water isn't subject to sudden temperature changes. Therefore it makes an excellent habitat for a cold-blooded animal. Another advantage is the water's ability to easily support body weight. Protoplasm has approximately the same density 1 as water, so a fish in water is almost weightless. This "weightlessness" in turn means two things: One, a fish can get along with a light weight and simple bone structure, and two, limitations to a fish's size are practically removed.

Yet there is one basic difficulty to living in water --- the fact that it's incompressible. For a fish to move through water, it must actually shove it aside. Most can do this by wiggling back and forth 2 in snakelike motion. The fish pushes water aside by the forward motion of its head, and with the curve of its body and its flexible tail. Next, the water flows back along the fish's narrowing sides, closing in at the tail, and helping 3 the fish propel itself forward.

The fact that water is incompressible has literally 4 shaped the development of fish. A flat and angular shape can be moved through water only with difficulty. And for this reason, fish have a basic shape that is beautifully adapted to deal with this peculiarity 5.


n.密集,密度,浓度
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
adv.向前;向外,往外
  • The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
  • He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。
n.食物的一份&adj.帮助人的,辅助的
  • The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
  • By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。
adv.照字面意义,逐字地;确实
  • He translated the passage literally.他逐字逐句地翻译这段文字。
  • Sometimes she would not sit down till she was literally faint.有时候,她不走到真正要昏厥了,决不肯坐下来。
n.独特性,特色;特殊的东西;怪癖
  • Each country has its own peculiarity.每个国家都有自己的独特之处。
  • The peculiarity of this shop is its day and nigth service.这家商店的特点是昼夜服务。
学英语单词
abattage
abdominal ganglion
Aconitum paniculigerum
aeromodellings
antisparticles
Arthropteris
asset bubbles
associationists
avernal
Bakonyszentkiraly
basic set
bending die
bitun
boohooing
breaks of day
brush position
cancer of glans penis
candy thermometer
Cardboard Box Index
classical rectification
clipper service
commercial zine
concludent
concussation
constant, force
converter short circuit protection
cut planning
demi mondaine
desilverized
device control unit
divinifying
eastlund
edemo
El Nispero
electro-beat
encasketed
epidemic hepatitis, epidemic jaundice
ermenegildoes
Erymanthus, Mount
Eumungerie
false alarm number
ferro-silico-manganese
finably
four-jaw independent lathe chuck
frequency meter of network
friction trip
funfests
gennie
harbord
hessian bag
higher differentiation
hogarth's
hook nail
i-witness
income tax reture
iodoformized
last pass own coding
licorice root
master processor program
medullary stele
medullectomy
mineral lease
moreen
motherboards
nitrogen trifluoride
nonsynchronic
Notrees
number of cycles
paretic neurosyphilis
partial elements
portliness
power wheeling
probers
quadruple bond
realized compound yield to maturity
reprives
reverse cascade
ringing repeater
rotary planing
round nose plier
sensational journalism
shaker cooling
shellful
sperrschicht cell
statistical demand analysis
straight tendon
task center
texturizable
thunderbirds
transformation of inverse hyperbolic tangent
transistor resistor circuit
van der waals' bond
Vandellia diffusa
Vanderbilt University
vesiculation
warm the cockles of someone's heart
Waskia
water cooled reactor
wax cutter
waywods
Welsh vault
wheat meal