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
accelerating grade
aeronautical communication station
allergy action code
allogonite
Ampliactil
aquae fontana
aquae gratianae (aix-les-bains)
borrowing costs
buffing paste
burst into the world
Calamus melanochrous
calder
cathodolyte
cedrin
centrelines
certificate of qualification
chill reducing inoculant
circumorbitals
classier
combinatorial arrangement
community development plan
complementarity of need
compound acetanilid powder
continuous wave nuclear magnetic resonance spectrometer
cushion matreial
dandelionlike
database handle
De-ionization Time
demethylations
discontinuous approximation
drainage tester
dysophylla
equivalent price
event probability
excessive lingual inclination
F-270
farepayers
farm household disease
flavorlessnesses
fumaruric acid
Gentiana pedata
geoponder
guttur
harmonic signal
hashes out
herring-buss
HTACS
Impatiens stenantha
indirect closed cycle
induction type wattmeter
inshipped
intercommunication panel
knar
last night
Litsea lancilimba
magnesite dolomite brick
Megaera
metal lot
minor planet
misery lit
Nabil'skiy Khrebet
nonopening
orgasmically
orthogonal latin cube
Ota's nevus
pan-americans
paramagnetic electron trap
pasteure crop
personal management analysis
pillaf
plate work
POL system
polyhydroxyphenol
priolepis boreus
Rolandian
round hole
runway observation
scubas
selective purchase
self-refutations
solay
southerners
spermatorrheas
standard scale
stationary solid bed
strengtheningly
sun glasses
supmmeatai triangle
Supramammillary
swab stick
sweatin
table lamps
Terråk
traffic on railroad flatcar
transduction(zinder & lederberg 1952)
truncated normal mean
tumourigenesis
under water reactor
unsportingness
vesuvius
water-tight work
yield class indication