全球水是如何分布的？其中淡水且可利用的部分占多少？
How is Earth's water distributed globally, and what fraction is fresh and accessible?
地球约97%的水是海洋咸水，淡水中绝大部分又被封存在冰川与深层地下水，真正可供人类直接利用的河湖淡水不足总量的1%。这种高度不均凸显了淡水资源的珍贵。
About 97% of Earth's water is salty ocean water, and most freshwater is locked in glaciers and deep groundwater, leaving rivers and lakes accessible to people at well under 1% of the total. This extreme imbalance underlines how precious usable freshwater is.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#全球水分布 #淡水 #可利用水资源
为什么九寨沟的湖水那么蓝绿透亮？
Why are Jiuzhaigou's lakes so blue-green and clear?
湖底碳酸钙结晶像天然“过滤层”让水极清，加上藻类和光线散射，水就呈现出梦幻的蓝绿色。
Calcium-carbonate deposits on the lake beds act like a natural filter, and with algae and light scattering the water shows a dreamy blue-green.
难度 进阶 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《十万个为什么》第六版地球分册,少年儿童出版社,2013
Ten Thousand Whys: Earth volume, 6th ed., Juvenile and Children Publishing House, 2013
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-7-5324-9328-9 · 核验依据 2 ISBN 9787532493289
#九寨沟 #湖水
水库（如三峡）在汛期是怎样帮我们防洪水灾的？
How does a reservoir like the Three Gorges help control floods in flood season?
汛期到来前先腾出库容，洪水来时把一部分水拦在库里、慢慢放，削减下游洪峰，保护两岸城乡。
Before the flood season the reservoir empties space; when floods come it holds back part of the water and releases it slowly, cutting the downstream peak and protecting towns.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#水库 #防洪
我们喝的水里一般有哪些矿物质？
What minerals are usually in our drinking water?
水流过岩石土壤时会溶进钙、镁、钾、钠等。适量的钙镁让水有“硬度”，也是人体需要的微量元素。
As water passes rock and soil it dissolves calcium, magnesium, potassium and sodium. Moderate calcium and magnesium give hardness and supply useful trace elements.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#饮用水 #矿物质
长江为什么被称为“黄金水道”？
Why is the Yangtze called a “golden waterway”?
长江江宽水深、支流多，从西部一直通到海边，能跑大船运货，航运价值极高，像“黄金”一样宝贵。
The Yangtze is wide and deep with many tributaries, navigable from the west to the sea by large ships, making its shipping value extremely high—like gold.
难度 进阶 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#长江 #航运
自流井为什么会自己往外冒水？
Why does an artesian well flow on its own?
当地下水被夹在不透水的上下两层之间的承压含水层里，含水层像一根被堵住两端的水管。若补给区地势较高，水压会把水抬到高于含水层顶部的位置；打井穿透上部隔水层后，水就沿井管自动涌出甚至喷成喷泉。这类井叫自流井，能自流的关键是承压水头高于井口。
When groundwater is trapped between two impermeable layers in a confined aquifer, the layer behaves like a sealed pipe. If the recharge area sits at higher elevation, pressure lifts the water above the top of the aquifer; once a well pierces the upper seal, water rises on its own and may even spray like a fountain. Such artesian wells flow because the pressure head stands higher than the well opening.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#自流井 #承压含水层 #水压
瀑布为什么会逐年“后退”？
Why does a waterfall retreat upstream over time?
瀑布顶部多为坚硬岩石，下方软岩被水流掏蚀崩塌，崖壁因此一点点向河流源头方向后退，如尼亚加拉瀑布。
A waterfall's hard ledge sits above softer rock that erodes and collapses, so the cliff edge moves slowly upstream, as with Niagara Falls.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#瀑布 #溯源侵蚀
什么是“南水北调”，为什么要调水？
What is the South-to-North Water Diversion and why move water?
我国南方水多、北方水少，工程把长江流域的水调到缺水的华北和西北，缓解北方用水紧张。
Southern China has surplus water while the north is short, so the project moves water from the Yangtze basin to water-scarce north China to ease shortages.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
中国水利部《南水北调工程》
China Ministry of Water Resources (MWR), South-to-North Water Diversion Project
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 pubmed-PMC3325841：The South-to-North Water Di
#南水北调 #调水
冰川是怎么从雪花变成几十米厚的冰块的？
How does snow turn into a glacier hundreds of meters thick?
高寒地区积雪多年不化，新雪把旧雪压实，排走空气变成粒雪，再在更大压力下重结晶成致密的冰川冰。冰川冰达到足够厚度后，底部在重压下会像软糖一样缓慢变形，并沿山坡向下流动，一年只移动几米到几百米。冰川既是水体也是缓慢流动的侵蚀工具，磨出U形谷等地貌。
In cold highlands snow persists year after year; fresh snow compresses the old layers, expels air to form granular firn, and then recrystallizes under great pressure into dense glacier ice. Once thick enough, the ice deforms like taffy under its own weight and creeps downhill, advancing only meters to hundreds of meters per year. A glacier is both a water reservoir and a slow-moving erosional tool that carves U-shaped valleys.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#冰川 #粒雪 #冰川流动
什么是“海绵城市”，它怎么对付内涝？
What is a “sponge city” and how does it fight flooding?
海绵城市用透水铺装、下沉绿地和蓄水池，让雨水能渗、能蓄、能慢排，减少暴雨时马路积水成灾。
A sponge city uses permeable pavements, sunken green spaces and storage ponds so rain can soak in, be stored and drain slowly, cutting street flooding in storms.
难度 进阶 · 适合 大众
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
住房和城乡建设部《海绵城市建设技术指南》，2014
Ministry of Housing and Urban-Rural Development (MOHURD), Sponge City Construction Technical Guide, 2014
#海绵城市 #内涝
夏天湖面常漂一层绿膜，那是什么？
What is the green film often seen on lake surfaces in summer?
那多是“水华”：水温高、养分（氮磷）多时，藻类大量繁殖铺满水面，会耗氧、发臭，影响鱼虾。
That is usually an algal bloom: warm water rich in nutrients (nitrogen, phosphorus) lets algae multiply and cover the surface, using up oxygen and harming fish.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#水华 #富营养化
地下水是不是“取之不尽”的？
Is groundwater “inexhaustible”?
不是。地下水靠雨水慢慢下渗补充，开采速度常快过补给，过量抽取会让水位下降、甚至井干。
No. Groundwater is slowly refilled by rain seepage; pumping often outpaces recharge, so over-use lowers the water table and can dry up wells.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#地下水 #补给
一场雨落到地面上，它的河水最终流向哪片海，由什么决定？
When rain hits the ground, what decides which ocean the river water eventually flows to?
分水岭是相邻流域之间的高地形边界，如分水岭山脊，落到两侧的降水会进入不同的河流系统。整个被分水岭围住、河水都汇入同一干流的区域叫流域或集水区，例如长江流域面积约180万平方公里。流域边界也决定污染物去向、洪水风险与水资源管理范围，所以治水必须先看懂流域。
A divide is the high terrain, like a ridge line, separating neighboring drainage basins; precipitation falling on its two flanks enters different river systems. The whole region drained into one main river is its watershed or drainage basin—the Yangtze drains about 1.8 million square kilometers. Basin boundaries determine where pollutants go, flood risk, and how water is managed, which is why water governance begins with reading the watershed.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#分水岭 #流域 #集水区
地下水都藏在哪些地方？地下水位为什么会变化？
Where is groundwater stored, and why does the water table change?
地下水储存在土壤和岩石的空隙中，能大量蓄水的透水层叫含水层，如砂砾层和砂岩；黏土等几乎不透水的叫隔水层。地下水位是饱水带的顶面，受降雨补给和抽水影响，旱季或大量抽水时会下降。地下水不断向河流和泉补给，是许多地区饮用水与农业的主要来源，过度抽取会造成水位持续下降和地面沉降。
Groundwater fills pores and cracks in soil and rock; layers that store and transmit it freely, like gravel beds and sandstone, are aquifers, while clay and other nearly impermeable layers are aquitards. The water table is the top of the saturated zone; it falls in droughts or under heavy pumping and rises with recharge. Groundwater continuously feeds rivers and springs, supplies much of the world's drinking and irrigation water, and over-pumping causes long-term declines and land subsidence.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#地下水 #含水层 #地下水位
为什么有的井水冬暖夏凉？
Why is some well water warm in winter and cool in summer?
地下温度变化很慢、常年接近当地年均温。冬天地面冷、井水显得暖；夏天地面热、井水显得凉。
Underground temperature changes slowly and stays near the yearly average, so in cold winters the well feels warm and in hot summers it feels cool.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#井水 #地温
水为什么被称为万能溶剂？
What makes water a 'universal solvent'?
水分子一端带正电、一端带负电，能拉开许多离子化合物和极性分子，把它们均匀分散。这种极性使水可溶解盐、糖等大量物质，因而有万能溶剂之称。
A water molecule has a positive end and a negative end, so it can pry apart many ionic and polar substances and disperse them evenly. This polarity lets water dissolve salts, sugars, and many other materials, earning it the name universal solvent.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#极性 #溶剂 #氢键
贝加尔湖为什么是世界最深的湖？
Why is Lake Baikal the world's deepest lake?
它坐落在地壳裂开的“裂谷”里，地层不断下陷，湖水就越积越深，最深处超过1600米。
It sits in a continental rift where the crust is pulling apart and sinking, so the basin keeps deepening; its maximum depth exceeds 1,600 m.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#贝加尔湖 #裂谷
沿海大城市为什么不缺海却常“缺水”？
Why do coastal megacities, surrounded by sea, often lack fresh water?
海水太咸不能直接用，当地河流少、污染和人口多让淡水供不应求，所以还得靠调水、节水和水库。
Seawater is too salty to use, and with few local rivers, pollution and huge populations, fresh water falls short, so cities rely on transfer, saving and reservoirs.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#沿海 #淡水
自来水有时有一股“消毒水味”，是什么？
Why does tap water sometimes smell of disinfectant?
那是加氯消毒后留下的微量余氯，用来防止水在管道里二次污染，一般量少、烧开或放置后会散掉，通常安全。
It is a trace of leftover chlorine from disinfection, which prevents re-contamination in pipes; the small amount dissipates when boiled or left standing and is generally safe.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#余氯 #消毒
湖泊是怎么形成的？
Why do lakes form?
雨水或河水积在低洼的盆地里，水排不出去，就汇成了湖泊。有些湖是冰川挖出来的坑。
Rain or river water collects in low basins where it cannot drain away, forming lakes. Some lakes fill holes carved by glaciers.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#湖泊 #水 #盆地
什么是泉水，为什么有的泉是温泉？
What is a spring, and why are some hot springs?
地下水从岩缝自然涌出地面就是泉。若水流过地下炽热的岩层被加热，涌出时温度高，就成了温泉。
A spring is groundwater that naturally emerges from rock cracks. If the water passes hot underground rock it warms up and emerges as a hot spring.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#泉水 #温泉
山里的泉水看起来干净，能直接喝吗？
Mountain spring water looks clean—can we drink it directly?
不一定。泉水可能带细菌、寄生虫，或天然含过多矿物质，最好烧开再喝才安全。
Not always. Spring water can carry bacteria, parasites or too much natural mineral, so it is safer to boil it before drinking.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#山泉 #饮水安全
为什么黄河的水那么黄？
Why is the Yellow River's water so yellow?
黄河流经黄土高原，裹走大量疏松的黄土泥沙，水因此发黄，下游还常淤积、改道。
The Yellow River crosses the Loess Plateau and carries huge amounts of loose yellow silt, tinting its water and building sediment downstream.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#黄河 #泥沙
河流是怎么把山谷切出来的？
Why do rivers carve valleys?
河水带着沙石不断磨刷河床和两岸，软岩被切深、硬岩留成台阶，时间久了就刻出山谷。河流是大地缓慢的雕刻刀。
A river carries sand and pebbles that grind the bed and banks, cutting deep through soft rock and leaving hard rock as steps, slowly carving a valley. The river is a slow chisel of the land.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#河流 #山谷 #侵蚀
水为什么会变成水汽？
Why does water evaporate?
太阳把水面晒热，水分子变成看不见的水汽飘上天空，就是蒸发。晒衣服变干也是这个原因。
The Sun warms the water and its molecules rise as invisible vapor; that is evaporation. It is also why wet clothes dry.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#水 #蒸发 #太阳
为什么水结冰时反而膨胀？
Why does water expand when it freezes?
大多数东西冷了会缩小，但水在结成冰时分子排成疏松的六角结构，占据更大空间，于是冰比水轻、能浮在水面。这保护了水下生物安全过冬。
Most things shrink when cold, but when water freezes its molecules arrange into an open hexagonal pattern that takes up more space, so ice is lighter than water and floats. This protects the life below from freezing solid in winter.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#水的反常膨胀 #冰 #密度
海洋里为什么有洋流？
Why does the ocean have currents?
风、地球自转和海水冷热不同，推动海水在大洋里循环流动，形成洋流。洋流像海洋里的河流。
Wind, Earth's spin, and differences in water temperature push the sea into looping flows called currents. Currents are like rivers inside the ocean.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#海洋 #洋流 #水
海啸是怎么形成的？
Why do tsunamis form?
海底地震或火山把大块海床猛地抬起，立刻推动上面整层海水形成长长的高浪。浪到浅海时堆得很高，冲上岸就很危险。
An undersea quake or volcano jerks the seafloor upward and shoves the whole water layer above it into a long, fast wave. As it reaches shallow water the wave piles up and becomes dangerous onshore.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#海啸 #地震 #海洋
极地冰盖为什么重要？
Why are polar ice sheets important?
南北极的巨厚冰盖把大量太阳光反射回太空，帮地球保持凉爽，还存着全球大部分淡水。冰一旦融化，海平面就会上升。
The thick polar ice sheets reflect sunlight back to space and help keep Earth cool, and they hold most of the planet's fresh water. If they melt, sea level rises.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
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Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#冰盖 #极地 #气候
潮汐为什么跟着月亮走？
Why do tides follow the Moon?
月球引力把正对和背对它的两边海水微微拉高，地球自转让各地依次经过这两处高水位。太阳也会帮忙，所以潮水跟着月亮走。
The Moon's gravity lifts the ocean slightly on the near and far sides, and Earth's spin carries each coast past those bulges. The Sun adds a smaller pull, so tides follow the Moon.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#潮汐 #月亮 #引力
海边的潮水为什么一涨一落？
Why do tides go in and out?
月亮用引力轻轻拉海水，海水就跟着月亮涨上来又退下去，成了潮水。
The Moon's gravity gently pulls the ocean, so the water rises and falls as it follows the Moon; that is the tide.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#海洋 #潮汐 #月亮
自来水从水厂到家，经过了哪些步骤？
What steps does tap water go through from the plant to your home?
一般先取水，再混凝沉淀去掉泥沙，过滤，最后加氯消毒杀菌，合格后才通过管道送到每家每户。
Typically water is drawn, then coagulated and settled to remove silt, filtered, and finally disinfected with chlorine before being piped to homes.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#自来水 #净水
河水为什么一直流不停？
Why does a river keep flowing?
水从高处往低处流，小溪汇成大河，就一直不停地向前跑。
Water always flows from high places to low places, and streams join into rivers that keep moving forward.
难度 入门 · 适合 幼儿(3-6)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Tarbuck & Lutgens,《Earth Science》第14版,Pearson,2015
E. J. Tarbuck and F. K. Lutgens, Earth Science, 14th ed., Pearson, 2015
#河流 #水 #流动