时间:2019-01-07 作者:英语课 分类:农业与发展


英语课

DEVELOPMENT REPORT

January 7, 2002: Storing Drinking Water


By Gary Garriott



This is the VOA Special English Development Report.


Safe drinking water has always been rare and valuable. Throughout the world, drinking water has to be stored for
periods of low rainfall. Tanks or other containers for water storage must be ready long before a dry season
begins.


For hundreds of years different kinds of materials have been used to build water storage containers. In many
areas of the world, small lakes or reservoirs 1 formed by dirt walls provide drinking water for villagers during the
long dry season. In western Sudan, the thick part of the baobob tree is removed to store water collected during the
short rainy season in that country.


Bricks 2 and concrete are among the modern materials used today to build storage containers for water. A solid
rock can be used as the bottom of a water tank. However, a mixture of rock and soil should not be used. The soil
will settle down, but the rock will not. The water will leak out.


Ferro-cement 3 structures are popular in some developing countries, especially in India. Ferro -cement is made by
pouring a sand and cement mixture over a skeleton 4 form made of steel rods 5, pipe, or chicken wire. It creates a
structure that is lightweight yet keeps in water. The walls of ferro-cement structures are usually thin, which
means that they can be used in building different shapes such as circles.


Wood also can be used for water storage structures. Cypress 6, fir, pine and redwood are some of the kinds of trees
that have been used. Wooden tanks do not require special care, although their average lifetime is shorter than
tanks made with concrete or steel. Any chemicals used to keep the wood from being ruined must not be
poisonous substances.


Water in uncovered 7 storage tanks or reservoirs can become unsafe. Small green plants called algae 8 can grow in
large amounts near the surface. The algae may help bacteria continue to grow, even if chemicals such as chlorine
are added to the water to kill the bacteria. Uncovered water also can be polluted by birds, animals or humans.


You can learn more about storing water for drinking through the Volunteers in Technical Assistance 9, or VITA.
You can reach VITA through the Internet at its World Wide Web address w-w-w dot v-i-t-a dot o-r-g.


This VOA Special English Development Report was written by Gary Garriott.



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n.水库( reservoir的名词复数 );储藏;大量的储备;储液槽
  • We must make use of our untapped reservoirs of talent. 我们必须利用我们尚未利用的人才。 来自《简明英汉词典》
  • The big storms in August refilled the reservoirs. 八月的暴雨又使水库积满了水。 来自《简明英汉词典》
n.砖( brick的名词复数 );砖块;积木;可靠的朋友
  • He compounded water, sand and soil and formed bricks. 他用水拌和沙和泥土做成砖块。
  • The United Auto Workers hit the bricks against General Motors. 联合汽车工人工会举行罢工,反对通用汽车公司。
n.水泥;胶结材料;vt.粘结;巩固
  • We need 100 tons of cement at most for this project.这项工程满打满算有一百吨水泥就足够了。
  • Let's cement the parts together.咱们来把这些部件粘接在一起吧。
n.骨骼,框架,骨干,梗概,提要
  • A long illness made a skeleton out of him.长期的卧病使他骨瘦如柴。
  • Her notes gave us just the bare skeleton of her theory.她的笔记只给我们提供了她的理论的梗概。
竿( rod的名词复数 ); 杆; (责打人用的)棍棒; 手枪
  • The wheels of the toy car were fixed on metal rods. 玩具车的轮子固定在金属棒上。
  • A typewriter in which the characters are situated on type rods. 一种打字机,其字符安装在字模棒上。
n.柏树
  • The towering pine and cypress trees defy frost and snow.松柏参天傲霜雪。
  • The pine and the cypress remain green all the year round.苍松翠柏,常绿不凋。
adj.无盖的,未保险的v.揭开…的盖子( uncover的过去式和过去分词 );揭露,发现
  • His head was uncovered. 他光着头。
  • A plot to assassinate the banker has been uncovered by the police. 暗杀银行家的密谋被警方侦破了。 来自《简明英汉词典》
n.水藻,海藻
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
n.援助,帮助
  • She called and called but no one came to her assistance.她叫了又叫,但没有人来帮。
  • He will get the great possible assistance.他将获得尽可能大的帮助。
学英语单词
19-norandrostenedione
adenomegalies
African American
ballin
baudotbetical order
bimolecular reaction
Bladderon
Blue Caps
Branigen
cataclastic strucutre
cataleptiform
Ceftazidime,ceftazidime
Centropus phasianinus
chain staring
closing cell
compensation pendulum
complementay transistors
concavously
conditioned medium
constant angle fringes
cordner
Council of States
crankshaft axis
CWR (chilled water circuit)
degree of food self support
dermology
dethronement
doggly
Dongara
double-pointed tack
doublet interval
duchesses of windsor
erythrosin(e) bs
exalting
ferrialliphanoid
field headquarters
fill-up
first order factor analysis
formation rate
free condition
gaussages
governor arm connecting piece
heat-insulating plate
houssaye
Hymenophyllopsidaceae
hyper urbanism
in-situ stress field
inner tubule
inventory model
ion beam polishing
Jachal
kudu
laser target designating system
leccinum insigne
litter-basket
loading pattern
logographer
macalino
mayhall
merdell
microphone switch
moon cross
moulded displacement
multiple familial polyposis
multiple files
myositis of guinea pig
nanocoating
nonmanifest
nuclear magnetic resonance magnetometer
organoaluminum
otis intelligence test
pinheiro
portland slag cement
preiere
preruption
preservation limit
pretest method
prolate spheroid
protecting bush
raised by wolves
registration of transfer in ownership
research scholar
reversal of gradient
Rydberg state
shelka
short-toed eagle
sink one's differences
slaveholder
slenderers
square steel
steer a steady course
Strait of Gibraltar
stream on
summyn
tele-encephalograph
thionyl dialkylamine
top dressing of fertilizer
transformer vacuum oil-filling
two-door body
valonia oak
variable pressure
windstream