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
2-chloro-6-nitrotoluene
5-cyanoindole
Abfab
acrolepis
Aleurisma
alfadex
alipogemetic
anastopoulos
apolipoproteinE
arcticization
azoles
balmat
benign calcifying epithelioma
Birkhaug test
by the benefit of
cargo inspection
ceus
change-pole moter
Chesterfield, Philip Dormer Stanhope 4th Earl of
code repeater
concludent
copper/copper-nickel thermocouple wire
cyst of thymo-pharyngeal duct
data mask
digastric fossa
double chamber sand blast apparatus
drum servo speed discriminator
dual-purpose sample
emdashes
emissivity at a specified wavelength
ethymylation
fall velocity
fish farmer
fixed end gondola
forelooked
funnelchest
gate inverter
Gelsa
geofact
governor gear
gramophone pickup
gross salary
hedge cutter
Heeten
helical polarization
hussonnet
hydro-oil sump tank
hydrocomion
hydrophysical law
intemperates
isthmia
jack-knife
jazz-fusion
lafavore
leighty
macroclitoris
methylene blue stain
molal average boiling point
mtoner
mucosae
myxoglobulosis
napellus
ngandon man
non-numerical tolerance
noncooperative constant-sum game
not-so-young
operational manual
outerly
paratyphoid serum
parupeneus biaculeatus
pass with
patient-centreds
planipennate
plunger linkage
polymeric membrane for separation
Pomorie
primary store
Prionodontaceae
round horseshoe arch
Scorsese
secondary seedling family
secondary stem villus
signal yard
simple screen management protocol
stress-tested
suprematistic
tetraethoxy silane
tetraose
tetraphenoxy-silicane
theatergoers
time-slice map
totally closed slot
trap control setting
trichosis sensitiva
ventilating mechanism examination apparatus
ventricular pressure
virgilidine
VLF radiation
wapperjaw
waste water treatment by activated carbon process
working the anchor
yakkers