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
acid rigidity
acting manager
advance of fund
ajahs
al-bashirs
armigeres (leicesteria) flavus
askos
association of lisp users
average people
band-type drying machine
basic report
BCVLV
bending moment (moment of flexure)
bequerel
bibliomaniac
bindbalk
board of executive directors
borescopy
brush forward lead
Building-timber
butterfly-nets
cavitating body
censored test
Common Access Method
computer switching
connections through marriages
conrail
consaf
contoured squeeze plate
cooperative relationship
coothay
core lamination
cross-examined
cross-spur
data distortion
drawbench jaws
effluent liquor
electrical winch
expanded function operator panel
extend help to sb
eye of a olute
feeler wire
ferroelectric memory
first-order derivative
fore-masthead light
free hole absorption
Fritz W. Meissner
geeksta
geothermal total flow system
graphiologist
hard winter wheat flour
identity-politics
injection wells
iodonation
iron schefferite
kyburgs
lamp cextractor
li-polymer system
lift lever
linear acceleration sensor
loose tooling forging
loverman
low-silicon pig iron
mad man
map contraction
moviego
multiprefix
mutual energy
non-random distribution
non-starters
not hold your breath
orbital eminence
Ouse River
owada
Padania
peak recognition
Pick disease
pill-box counter
proencephalus
proper packing
put ones foot in ones mouth
retinal detachments
rihga
sample charge
Satellite Convention
Serentil
Sigalionidae
single or return
skeletal dolomolds
solder ball
sprocket shift claw
stem-pessary
stonemason
struck notch
telecommunications technicians certificates
terbufibrol
thermoelectric manometer
thermoelectrical alarm
towed flexible barge
truly linear
ventricuIar felds
welfare assistant