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
activized
adapter bearing
adaptive distributed minimal spanning tree algorithm
akoka
alimentary lipemia
amnioss
anilidic
anxiety-ridden
associationism
austrian airlines
back labors
Bad Schallerbach
beginner
biomethanation
blanket gas analysis
borrowest
bulgren
cat (children's apperception test)
clk.
cock-and-pie
comprime
crash out
cross-country flight
crystal clathrate
derivative rights
dirty poll
Do as you're bidden and you'll never bear blame.
down-draft manifold
dressed to the nines
El Salado, R.
elastic limit in shear
Elatostema subcuspidatum
elbe (labe)
electrical anemometer
equitative
feedthrough capacitor
fertilizer-distributor
field ampere-turn
fight to a finish
flauntily
flexibility matrix
floating thumb
fogden
fourth stage
Gornovodnoye
harping
hiked up
hitch roll
hypertypic
inamoratos
Indigofera rigioclada
industrial-instrument
intestine loop
iris scan
Kaliningradskaya Oblast'
left dorso-posterior position
loss due to anchorage temperature difference
ludent
marine centrifugal type refrigerating compressor unit
metallibure
milch goat
neisseria gonorrhoeaes
nonhierarchically
Nymphula
objective cap
office speaker
oozier
other multimode fiber optic cable
pajamas
panama, gulf of
personal allowances
podheads
Port Noarlunga
quod erat faciendum
radiator thermometer
rallentando
re-furbish
rhinoneurosis
river inversion
rotary expansion engine
sagaciate
sand pike
Saxifraga triaristulata
smooth-bore
Solana
soloman r.
spalike
spiking maul
stationary-welding machine
strongbark
swirl defect
teleprinter receiver
thiamins
Third Lateran Council
time interval analyser
ultrarunner
unrecorded income
unwashable
vapour transport
variable structure computer
waggonwright
yellow paper test