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
aedaeagus
amerveille
anaerobe
anti-La
auditory sensation area
bacterial arthritis
barasch
bayonet arrangement
beer parlours
beta-imidazolylethylamine
biological radiation effect
bioplans
bluma
bread baking
chemosorption
Chrysosporium
compensating dollar
cornishman
Cromwellian chair
crouchant
cypripedin
dielectrics
dismemberment of property
Durwalē
ezekiass
fading puppy syndrome
fatty streak
feists
Feringees
fick
foursenery
free-piston manometer
generalized nodal displacement
glycerinated lymph
grimmia handelii
heavy lifting wharf
heterotransplants
high speed cutter
iia
inherent noise of microphone
initial error
Interior Secretary
jiddi
kinetic consonant
kneweth
knoedler
kolmogrov
krasnoturinsk
last channel
linear process
look in on
lucee
magnetofluiddynamic
marital crime
MCEB
monopoem
moorn
Munchique, Cerro
nepuite
nickel anode
non perishable cargo
Oreocharis obliqua
outglittered
overboard falls
overparameterization
pang pang wu
pharmaceutic industry
phenol water disposal
physically impaired
planned spacing of birth
plotform
pneumotyphoid
reversible clutch
revirement
right of rescission
rsi
scotch broths
scsi -3
seamers
share exchange offer
Shinhung
sievers
small-wares
smitten
son-of-a-bitch
special subdivision
spring wind-up
stealthy aircraft
steering gear housing plug
sugiol
sulfogalactosylglyceride
sulzbach
switch fuse
temporary trade
twist blades
unforeseen
unpackaging
ussingite
valveless compressed-air distributing mechanism
volume compression and expansion
wellconnected
wing-tips