时间:2018-12-03 作者:英语课 分类:初学者听力文摘精选


英语课

Fish live in water, but do they drink it?



The answer is yes, but how fish drink water depends on where they live.



Water gets into a fish's body through osmosis, the process in which water diffuses 1 from a higher to a lower concentration. For example, if there is more water outside of a cell than inside, water will try to flow into the cell until there is the same concentration of water on either side of the cell's membrane 2. The body of a fish acts the same way, either absorbing or losing water depending on its surroundings.



Whether a fish absorbs or loses water is based on the fact that all fish must maintain a certain amount of salt in their bodies to stay healthy. Fish that live in fresh water have a higher concentration of salt in their bodies than the surrounding water. Consequently, water continuously flows into the fish's body to attempt to dilute 3 the amount of salt in the fish until it is equal to the amount of salt in the surrounding water. Since fish cannot allow their salt content to be diminished, their kidneys work overtime 4 to expel excess water in the form of urine.



Ocean fish have the opposite problem. Surrounded by salt water, their bodies contain a relatively 5 lower concentration of salt than the ocean water. In this case osmosis causes the fish to constantly lose water in order to equalize salt concentration inside and outside the fish. to partially 6 compensate 7 for the water loss, ocean fish actually drink water through their mouths. And to get rid of the excess salt they take in by drinking seawater, they excrete some salt through cells in their gills.

 



1 diffuses
(使光)模糊,漫射,漫散( diffuse的第三人称单数 ); (使)扩散; (使)弥漫; (使)传播
  • A gas in solution diffuses from region of greater to one of less concentration. 溶液中的气体由浓度较高的区域向浓度较低的区域扩散。
  • The sun diffuses light and heat. 太阳发出光和热。
2 membrane
n.薄膜,膜皮,羊皮纸
  • A vibrating membrane in the ear helps to convey sounds to the brain.耳膜的振动帮助声音传送到大脑。
  • A plastic membrane serves as selective diffusion barrier.一层塑料薄膜起着选择性渗透屏障的作用。
3 dilute
vt.稀释,冲淡;adj.稀释的,冲淡的
  • The water will dilute the wine.水能使酒变淡。
  • Zinc displaces the hydrogen of dilute acids.锌置换了稀酸中的氢。
4 overtime
adj.超时的,加班的;adv.加班地
  • They are working overtime to finish the work.为了完成任务他们正在加班加点地工作。
  • He was paid for the overtime he worked.他领到了加班费。
5 relatively
adv.比较...地,相对地
  • The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
  • The operation was relatively painless.手术相对来说不痛。
6 partially
adv.部分地,从某些方面讲
  • The door was partially concealed by the drapes.门有一部分被门帘遮住了。
  • The police managed to restore calm and the curfew was partially lifted.警方设法恢复了平静,宵禁部分解除。
7 compensate
vt.补偿,赔偿;酬报 vi.弥补;补偿;抵消
  • She used her good looks to compensate her lack of intelligence. 她利用她漂亮的外表来弥补智力的不足。
  • Nothing can compensate for the loss of one's health. 一个人失去了键康是不可弥补的。
学英语单词
a gust of wind
above deck
acute occlusion of artery
aerotropolis
alphabetic coded character
Astrolipoma
auxiliary air reservoir
BACKSPACE statement
balanced binary search tree
bead roughness
Bornes
built - in function
carbamino alanine
check for 100 dollars
computer control console
cotranscriptional regulation
cournot profit
cytopathogenic
doubly-balanced modulator
effective decay constant
Eleusinian marble
Eocambrian period
festiveness
frank caro process
giella
Gilmer County
go beyond
heptanethiol
Hi-alazin
high-keier
hospital controls
impurity diffusion coefficient
incloud
JD Edwards EnterpriseOne
kinone
law of convertibility
leyhausen
link board
loadsamoney
Luzula sichuanensis
major element
Medichol
meetels
mobile home
modificatory
modified gunmetal
module pulse converter
monorchidism
montesite
multi-burners cutting machine
nanomia cara
newsmaking camera
non operative
nonsymbiotic
nuons
okamejei kenojei
onnagatas
penetrating varnish
pennoncier
peripheral dimension
phos-silver braze alloy
Piesporter
profilings
propagational
propulsion machinery order
prothonotary warblers
psychopathic personality disorder
PTF
public charity
punching in
quicksetting level
Raphidiidae
rapid access management information system
RDT (resistance temperature detector)
rose globe lily
satellite transmitter
scrap-heaps
self-checking device
self-perpetuating cycle
semiconductor absorbers
seths
single-page
slow-bellied
snipe
soft gel-like matrix
spatangids
Spergula maxima
stepashin
structural parachor
stubble breaker
subluxation of carpus
supporting steel plate
talebearer
tank hose strainer
Termalgin
torstars
totally-inclosed airplane
tripole
tuned mass damper
tunnel cleanroom
vacuuming metalling
waramaug