首页
登录
职称英语
[originaltext] Today, most countries in the world have canals. Even in the 2
[originaltext] Today, most countries in the world have canals. Even in the 2
游客
2023-09-12
45
管理
问题
Today, most countries in the world have canals. Even in the 20th century, goods can be moved more cheaply by boat that any other means of transport. Some canals such as the Suez or the Panama, save ships weeks of time by making their voyage a thousand miles shorter. Other canals permit boats to reach cities that are not located on the coast. Still other canals drain lands where there is too much water, help to irrigate fields where there is not enough water.
In places where it does not rain very often, irrigation canals drain water from rivers or lakes such as the lake behind the Aswan Dam on the Nile River, and provide the irrigation water.
In places where there is too much water, canals can drain the water off the land for use in fanning. In Holland, acres and acres of land have been drained in this way. Since much of this drained land is below sea level, the water in the canals has to be pumped up to sea level. Dikes have been built in Holland to keep the sea from covering the land, as it did in the past.
Canals are also used to carry water to mills and factories. The water from a river is kept at a higher level than the river until it reaches the wheel of the mill. Then the water is poured over un61 it reaches the wheel of the mill. Then the water is poured over the mill wheel, making it turn. The same principle is used in more modern factories and in hydroelectric generating plants. The force of the water, falling from a certain height, provides a cheap way of producing electricity.
选项
A、Navigation.
B、Drainage.
C、Irrigation.
D、Electricity.
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3006984.html
相关试题推荐
[originaltext]WhenpeterandRosecametotheUnitedStatesfromthePhilip
[originaltext]Todayschoolchildreninmanycountrieshavehighratesoffa
[originaltext]Todayschoolchildreninmanycountrieshavehighratesoffa
[originaltext]Todayschoolchildreninmanycountrieshavehighratesoffa
[originaltext]Aftertravelinginacrowdedbusandwaitinginthenoisyair
[originaltext]W:Hi,Sam,IhatetobotheryoubutIwonderifIcouldhaveaw
[originaltext]W:Howdoyoufindyournewapartment?M:Well,it’squitenicere
[originaltext]W:Howdoyoufindyournewapartment?M:Well,it’squitenicere
[originaltext]W:Howdoyoufindyournewapartment?M:Well,it’squitenicere
[originaltext]W:Howdoyoufindyournewapartment?M:Well,it’squitenicere
随机试题
Manypeoplewronglybelievethatwhenpeoplereacholdage,theirfamiliesp
中共十七大报告指出,中国国家发展战略的核心、提高综合国力的关键是( )A.走新
B
根据以下资料,回答121一125题。 从1979年到2007年,
证券公司、证券投资咨询机构提供证券投资顾问服务,应当与客户签订的证券投资顾问服务
根据两个变量的18对观测数据建立一元线性回归方程。在对回归方程作检验时,残差平方
对于需求价格弹性分别为1、1.5、0.8、2.0、1.25的甲、乙、丙、丁、成五
1999-137.处方用北五加皮系指 A.短梗五加皮B.细柱五加皮C.杠柳
鉴定药材外形完整或特征明显的破碎药材的首选方法是A.基原鉴定 B.性状鉴定
急性阑尾炎;当腹痛尚未转移至右下腹前,在诊断上具有重要意义的是 A.出现发烧
最新回复
(
0
)