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
activo
ad litteram
adequate stimulus
afore-mentioned
arkoun
atom craft system
atterberry
auto-manual
autozeroing
ball passing test
bcoas
black nucleus
blueprinted
bombus sonani
brake hose pipe
central procurement
cinnamon bear
clear-headed
coinfections
correction of scale difference
crotts
customers ledger
dash something off
demineralises
direct injection diesel engine
disaster avoidance plan
dry crop
ecclesial
ejector type dredger
endophenazine
fictitious variable
French dressings
fried mixed vegetables
gas electric automobile
Gratian
had no effect on
hamaspora hashiokai
heat cramps
hedgehog concept
hydraulic overload
identicalextracellular
imbricated fault zone
jacquard pattern
Javarthushuu
judgest
kawakita
Kootenai series
Kope loff modification
Kumkuduk
lighting tariff
lock-in range
long bridge house
Loubetsi
low vacuum filling machine
low-speed camera
majority voting system
male-only
man-machine interface design
mark hold
Meromyza saltatrix L.
miaouing
mixed type occlusion
monbrison
morbid symbolic thinking
mulch spreader
muscled up
myoneuralgia
Navaglobe
neutrina
nontonal
Noordbroek
order sapindaless
Oxyaena
particle aggregation
pontoon-type breakwater
prosecutor general
put to flight
quelched
quittance
revenue account
roation
rook pawns
scaling back
sea front
secateurss
servillia formosensis
showq
sigmoid gyri
silk-oak
succession pattern
syntactic calculation
test cable
The mills of Good grind slowly.
thermal turbulence
thrash something out
tibiad
tobacco-plant
Trosy
untimeable
very-short-range radar
waldheimite
wraths