首页
登录
职称英语
What does the passage mainly discuss? [originaltext] Canals are watercourses
What does the passage mainly discuss? [originaltext] Canals are watercourses
游客
2023-11-20
15
管理
问题
What does the passage mainly discuss?
Canals are watercourses constructed to improve and extend natural waterways. They are generally built to facilitate transportation, but from the beginning they have been used for many additional purposes including draining swamps, irrigating land for cultivation, and promoting economic development.
Canals are often classified by the size of vessel they can accommodate. Some small local canals, which are able to float only 100 to 300 ton boats or small rafts of timber, may be only 3 feet deep. Major barge canals generally range from 6 to 9 feet in depth, and some are as much as 10 or 12 feet deep. These canals can carry 1,350 to 2,000 ton craft. Ship canals are 25 feet or more deep and are capable of accommodating large vessels in the seagoing class.
Canals may also be classified as either water level or lock canals. Water level canals do not vary in height along their courses. The best known of these is the Suez Canal, which is at sea level. Lock canals, which include most modern waterways, contain locks, or special devices for raising and lowering boats along their courses by changing the depth of the water. Each lock is a stretch of water enclosed by gates at each end. After a boat enters the lock, water is let or drained out until it reaches approximately the same level as the water ahead.
选项
A、How canals are constructed.
B、Common types of canal boats and barges.
C、The world’s largest canals.
D、How canals are used and classified.
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3204624.html
相关试题推荐
Whatisthemaintopicofthisconversation?[br][originaltext]M:Weseemtob
WhatdidHelenrecentlypass?[br][originaltext]M:Hi,Helen.Howdidyourdri
Whenistheguidedtourofthecampusgiven?[originaltext]M:I’mhereforthec
Howmanyoldpeoplehavebeenexaminedfortheresearch?[originaltext]Doct
WhichofthefollowingisNOTtrue,accordingtothepassageyouhavejustheard
WhichofthefollowingisNOTtrue,accordingtothepassageyouhavejustheard
Whatisthespeaker’sattitudetowardsheavymetalmusic?[br][originaltext]
Whatisthespeaker’sattitudetowardsheavymetalmusic?[br][originaltext]
Whatisthespeaker’sattitudetowardsheavymetalmusic?[originaltext]Mus
Thespeakeristalkingabout______.[br][originaltext]Fantasyisatough
随机试题
Whatdidthewomandolastnightaccordingtotheconversation?[br][originalt
Hemingwayoncewrotethatcourageisgraceunderpressure.ButIwouldrathe
Okay.YourememberthatI’vementionedthatit’simportanttoreadthe【B1】__
马克思主义世界观教育主要包括()A.辩证唯物主义教育 B.马克思主义认识论教育
A.信石B.石膏C.赭石D.朱砂E.雄黄断面具有树脂样光泽的药材是
2020年,H省全省地区生产总值43443.46亿元,较2019年减少2384.
稳定价格水平作为一个政策目标,是指每种商品的价格固定不变。()
旅客随身携带的行李物品适用()报关程序。A、“红绿通道”制度 B、进出境报关程
影响短期汇率变动的两个关键因素是()。A.经济发展水平和增长速度 B.经济实力
当工程项目实行施工总承包管理模式时,业主与施工总承包管理单位的合同一般采用(
最新回复
(
0
)