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
'Aqrah
Akira Kurosawa
Albizia bracteata
andel
ascitis
auto dialler
begawans
Blowing Rock
burnt velocity
capital of Malaysia
cascading style sheets
compensation-type voltmeter
coquinoid limestone (coquinoid)
counter-weight
Cremanthodium coriaceum
cycle of vibration
Debyes equation
departees
diffuse tissue
distorters
duck type aeroplane
endotoxaemias
Ernst Boris Chain
exchange earnings
finite topology
fishman's anchor
fleet support unit
four-doors
greger
heterodimerise
high temperature cemented carbide
hudspiths
hypotheticals
identity system
Impatiens chimiliensis
indefinite shipment
indexing type
interchange price
intransparency
isentropic compression
jentel
keratohyalinlike
Kubuna
liquor coneae
lundt
magnetic head material
magnetoperation
medialects
meningoencephalocystocele
mereness
mingledly
missel-bird
multicast scheduling
network environment
nozzle chamber
object program listing
objective probability distributions
occur span start date (33)
oganse odori (japan)
OR mapping
order Aristolochiales
Parang, Pulau
pash back wheel
permanent virtual path connection
piston manometer
platen drier
pot-housey
racicot
rack-and-pinion adjustment
radio telegraphy
rate of production
ratio change gear
retail mark-up
retainer with balls
rhizomelique
rhomb spar (dolomite)
rice crispies
Rio Negro, Pantanal do
risk system
royster
rustow
Saint Agatha's disease
Salmonella foetida
samplery
sculptures
seiriasis
simmondsia california
stator ampere
steroid chemistry
sticky wicket
swine-herd
take a wild guess.
tax-advantaged
testify on sb's behalf
thumb tack
token code
trammel wheel
universal sttachment
university graduates
vestures
wood sheathing
wrosse