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
adiabatic saturation pressure
algesias
always safely afloat
anticyclonic inversion
antitheists
aromadendral
arts therapies research committee
as tender as a chicken
bar iron crane
barera
be stuck up
burry blanket
Busachi
cardiopep
carry the torch
cerithium munitum
cesari
Congressional documents
cross toe forward pointing
double print down
dynamic trim
e-teacher
ecostratigraphic unit
edge disjoint cut-set union
El Bozal, Sa.
electropolarized
ellingsen
entrained bed
Eupteleaceae
Evinos Potamos
file preparation
fire salamanders
forelong
frying-pans
gastricsins
gazed
gentoo
glow-discharge lamp
Hedysarum chinense
Hibiscus fragrans
homespunness
hortvet freezing test
Huygens' principle
in-observance
infeodations
jet-sets
little chief hare
local central office
long-tailed tit
lorned
lounging robe
Mecoffaminum
megatons equivalent (mte)
micro-size particles
munication
munion
needle-applicator
Nettilling L.
new-formed
oatmealy
Padisal
part learning
pemphigoid syndrome
planetary thread miller
positive credit
potassium aluminosilicate
Prud'hon, Pierre Paul
radiocarbon age
residual value of land
ride the fence
roapy
roentgenokymograph
RR Lyrae stars
salpausselk? subglacial period
schizomycete
scrap rubber
secondary aliphatic monohydric alcohol
seismicrophone
semiopened
sieve method (mechanical analysis)
signal intelligence report
single front wheel tractor
sir herbert read
spin gearing
spring-loaded overflow valve
square bloom
stability under UV illumination
supervisory boards
surge withstand capability
tasselseeds
temperature measurement
tennising
terminator codon
Tetraodontoidei
thermoelectric energy conversion
threshold of relaxation
Typha domingensis
underlain
vernonia
virtual classroom
water trade
Wesson