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
-s
5'-Deoxyadenosyl-B12
acid fast red
Aegerita
albumin milk
almeida pilosa
amoralists
amphoteric ion-exchangeresin
anti-impact gear
batouti
blast furnace smelting
bunss
cabinetmaker
cauliflora
CD Video
Churumuco
COBOL transaction program
collapsible keel block
corecipients
dihydropyrimidinase
direct exporttrade
draw-
drip-drying
escrowing
esterifiable
Ethydan
ethyl cyanamide
filtered signal
fire bricks
flamdoodle
Florence crystals
foam solution
folded potential
forestry production statistics
fully arisen sea
general fixed assets group of accounts
genus Hamamelis
genus irenas
Grecian nose
groaners
Guengant
Haskins
hcb
ill-humo(u)redly
in conjunction with
input/output stream control
inseminating catheter
insured risk
joint buying office
Kentish fire
lande's g factor
Lincolnshire
look-at-me signal
magon
managed economies
merphenyl
metropolitan broadband network
mobile control room
Muncimir
national switching network
network for arc welding
non-metered tap
not the done thing
nuclei cochleares
Oetinghausen
pastures newer pastures
Pelargonium limoneum
pen lid
penetration method
permeably
Ping Pong buffer
powerful radio-frequency cable
pump for sludge tank
punctuation space
Quinalspan
redalder
reduced flange
regulating error
requirement for tax exemption
self-skill
shape straighten
shelf front
ST_including-and-excluding_covering-and-adding-layers
suele
taper-reamer
taste acuity
technico-
telecommunication route
throw up one's hat
transiliac
travel card
triatic
uncountry
variation in testing temperature
vibroplatform
Villaputzu
Virtual File Allocation Table
vision distance
well-illuminated
what are we waiting for
yester-morrows
z transform inverse