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
Abihail
abstenious
accelerating thermal aging test
acinitis
AG linac
air delops
allylic migration
always will
Ammons horn
anemone quinquefolias
attributional complexity
bangia fuscopurpurea lyngb.
barcol hardness test
benignities
Bromochlortrifluoraethanum
cachexia exophthalmica
Campobello Island
centre bearing housing
chopper bicycle
cog belt
commodity depreciation
computer image
condition for inelasticity
cpu info center
crapplications
customs line
Desmarestiales
didymia
dip needle
dogleg fence
electrotropism
epidemic diarrhea of nemborn
exclusively preferences in force
exigence
family trachipteridaes
fathallas
fawn-colored
finance of education
finger support
flight clothing
genealogizing
Isaacs-Ludwig arteriole
isoglutamine
jsf
Kirkstall
Labadists
Lancashire boilers
latifiyah
lay down to
lenthalls
long-path multiple
lyxulose
magnetic dipoles
manueline-style
map reading
megascolecids
microbia
mokros
Moudzanga
mucous coat
Nanortalik
Nizhneangarsk
non-bolter
nonunitary representation
ore reduction
organization for combat
outlet box
planed fault
plasmagynogamous(michaelis 1955)
power refer to engine room unit volume
primings
quadrigal
recess of thread portion
reversed stress cycle
rhaphiolepis japonica s.et z.
risk-returns
sequence components
Shapsha
Silvio
sinfonias
snow water
sodium ethylmercurithiosalicylate
spacing piece
split anode
sportscards
Sternbergia lutea
subsonic ejection seat
surface culture
swindlings
switch ... on
switchboard attendant
torpedo-firing director
vacuum gripper
Valecor
valiantness
wilderness program
with average irrespective of percentage
yester-year
zinc oxides
zinkbotryogen (zincobotryogen)