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
(traffic) bollard
acetylcimigenoside
Ammannia auriculata
ammonia-free
auroral echo
basic tactical unit
bioimage
boring machines
breathing bag
brounckers
camping sites
Chalisgaon
chaos field
cholopleth map
clearance zone
clearly erroneous
Cochliomyia bominovorax
coplaner force
cosustainers
cubic decimeter
Dehydrocholic
depauperates
dynamically equivalent model
economic rate of return
El Coco
elets
english corn
epicurious
flexible sealant
FOIA Freedom of Information Act
fronto-squamosal arch
gate of a except b
goaded
grrrr
handdown
hauling duration
have trouble
idle air control
index disk
instant centre
insulation safety glazing material
invisible fat
Izoplit
karski
Katata
liquid oxygen fill-drain auto-disconnect connector
medium-chain triglyceride
member of tribunal
metallo organic chemical vapor deposition
Michelia fuscata
microecology
mineral flax
myriophyllum ussuriense maxim.
national bourgeois industrialists and merchants
negative sloping yield curve
network and trunk control
notification code
oil varnish
one man band
panelus crenatus
part operation file
paying back
physics of elementary particle
pityriasis maculata et circinata
prompt neutron area
pulmonary talcosis
pulse rhythm
quint
re-let
relied upon
risk premium rate
sahut
secure application module
Semipalatinskaya Oblast'
shlachter
shuttle box
silver birch
slickensides
sp vol
spatial scale
spatterware
stall-warning unit
structured media
stump neuralgia
tactical training
taking someone out
tanji
TjC
toilet-training
top-down analysis procedure
trussed portal
Turnbull
umbellal
underproduced
unserviceable ammunition
vacuum ingot melting
vainly hope for
watch your step
whumpage
workfree
xenbucin
zenith nadir axis