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
a favourite son
acetylcytidine
Actinidia suberifolia
advanced research and development activities
aerotank
anaphylactic response
animable
anterior end
antithetically
bacterized
barkor
be inspired by
beijing-baseds
binary-coded range time signal
buckle arrestor
certified composition
chained mode
chest voice
cholesterogenesis
circular index
clear pass
colo(u)red fog
continental philosophy
cyprioter
Dermatoplasy
dethridge meter
diaphragmatic herni
douglas-homes
extremists
Florida Bay
force an issue
full power to conclude a treaty
fused phototransistor
GCAW
general purchasing power of the dollar
globe lathe
Hismaic
i-grede
infiltered
Koolunga
Langenhain-Ziegenberg
leaky waveguide antenna
letter card
lever collar
live animal back-fathickness
major general
Masihi
mccrae
menopausal arthritis
meter-out
mock leno
moisture control
Monocerids
monoethanolamine oleate
neuraminate
NFC Forum
noma pudendi
non-cooperative equilibrium
non-rights
non-volatile residue
outstares
pan rivet head
patriotic democratic personages
philagra kuskusuana
piedmont zone
plowed
pot-ale
protected person
pseudocarchariid
real-time information data base service
refdanskite
reinforced concrete draught tube
reservoir evaluation
sagita
salt depletion syndrome
screen for sidelignt
screw caliper
sieving action
Sir Edward Victor Appleton
sleep sth away
special clauses for live stock
Spironema carteri
St-Jean-de-Sauves
Ste-Croix-Volvestre
stent skin grafting
still-hunters
superobeses
surface treating
tape worm
Telok Ayer Estate
terriere
time domain analysis
towsack
trans-activation
triode-hexode converter
Ts'khneti
umari
underlying net
Utting am Ammersee
wall of wound
waterfowl alignment
wholly inherent buoyancy type lifejacket