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
23
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
Airpollutiontriggersmoreheartattacksthanusingcocaineandposesashi
Puttingfeelingsintowordsmakessadnessandangerlessintense,U.S.brain
[originaltext]W:Prof.Williamsdidn’ttellmethathislecturewaspostponed.
水轮机主要过流部件中,()是水流进入水轮机经过的第一个部件,通过它将水引向
氨基糖苷类抗生素的主要作用机制是A.抑制细菌细胞壁的合成 B.作用于细菌核蛋白
下列关于公共行政的主体表述中不符合规定的是()A.独立行政机构属于政府行政机
关于凯恩斯的货币需求理论的说法,错误的是()。A.凯恩斯认为,当利率降到某一低
下列方法中,可以用于风险识别的方法有()。A.解析法 B.德尔菲法 C
供热管道焊接前应根据焊接工艺试验结果编制( )。A.焊接工艺方案 B.质量计
(2021年11月贵州真题)甲施工企业在某条公路的施工过程中,需要购买一批水泥。
最新回复
(
0
)