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
aporocactus flagelliformiss
areal context
auto-load balance
bayes solution
be studded with
blackmon
boundary layer climate
cadmium-propylxanthate
celdt
ceramic dielectric capacitor
cet-
cisacting
columnae rectales
complementary colour removal
contact service
de-tunings
delayed-neutron fission spectrum
dewwater
dispensationalist
disships
double linear stage pattern
draw-bar pocket
drill headroom
emotional contagion
emperor-worships
etidronate disodium
Euthynnus
eye-rolling
femtojoule
fiberglass-reinforced plastic
filling hose
first-order subroutine
fixed fire extinguishing system
flask shaker
fluorimetric method
free user resources
frequency sharing scheme
frozing
gasoline drum
genus Basiliscus
glide system
glueocerebrosidoses
gnomophobia
hand turning tool
holoway
host service station transfer protocol
hungerbeeler
iep
impression hardness testing
IPFP
jaspagate (agate jasper)
Kanayevka
kellars
lightning tooth cross-cut saw
locker-gowlan
mccann-erickson
microgovernments
mildewy
molar mass exclusion limit
mount st. helenss
multiple digital recording
nanocameras
Otter I.
paysite
photo calibration mirror
phyllosticta wikstroemiae
population at need
Potentilla luteopilosa
pressure twin
private classroom
prolapse of mitral valve
PSLT
psychological novel
quasi-circular
reflected resistance
routing
sajong soil
schiavo
segmental bearing
semidiameter
Sennar State
sentence-completions
shope fibroma (of rabbit)
spherical micelle
stationary meteor
store program
strictly ergodic
sturdy
stussy
supplementary design formula
switching tube
take up a bill
thermal impedance under pulse conditions
thioglycol(l)ate medium
transilition
Trigonotis corispermoides
uniacidic base
Unity of Science movement
window counter
word building
yellowweed
Yenidamlar