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
accommodation and food service activities - isic
ammo-
articulationes ossiculorum auditus
artificial cotton
asterubin
back analysis
baronial
Bernkastel-Kues
biology of carbohydrates
bisacrylamide
burdenening
carbonyl platinous chloride
catecholaminergic recptor
character format memory
chemiluminescence immunoassay
circular striation
Citlaltepetl
clear cell carcinoma of kidney
coelioxys fulviceps
cometary halo
command language
Cormick
Ctenopsyllus
current-controlled NDR
dakhma
Dare County
data accessibility
differentiated products
direction of turning
dropping by
Duchenne-Arandisease
dynamic function of money
eccentricity detector
eczema intertrigo
electron-beam welding
end of line
engine room register
Evans Str.
follow focus attachment
foreign currency amount
fringe sharpening
frontal branch
gamma-ray signature
have weight
hot-air-turbine combined cycle
i-halden
indisetron
Inebolu
information reports
issuing station
jedlicka
Koblyakovo
kritz
labiomental curve
lesser flamingo
Lime disease spirochete
Linakhamari
liner rerms
live programme
Lycra
measure of relative value
mechanization moulding
mosel
mry
nanocomputers
natural resource economics
non detonating combustion
noninheritance
obstructionism
one's foot has gone to sleep
order convergent filter
paraffin removal
Pectenidae
pixelmap
polities
pre-programmeds
primary trainer
psychrometric regulator
pukwana
rated back-to-back capacity bank breaking current
reactor fuel pellet
reconnoitred
reversing screw bolt
Rhododendron nakotiltum
sacrafice
Saulgrub
selector installation
set temperature
size-exclusion
spars
specific ion effect
splice cable
starting posts
steady-state incompressible flow
superluminescent diode
supporting back
time-sharing supervisory program
tolagnaro (fort dauphin)
transverse vibrater
Uninstall Manager
unrehearsed
unstable operation