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
2024-11-01
24
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 a- long 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/3827183.html
相关试题推荐
Accordingtothecourtruling,Israelhasto[originaltext]TheInternational
Wheredoesthisconversationmostlikelytakeplace?[br][originaltext]M:Hell
Hewantstofindsomeonewith______hecoulddiscusssuchquestions.A、whoB、who
Whatisthemaintopicofthisconversation?[br][originaltext]M:Weseemtob
Whatisthemaintopicofthisconversation?[br][originaltext]M:Weseemtob
______werereportedbytheweatherstationinChicago.[br][originaltext]
______werereportedbytheweatherstationinChicago.[br][originaltext]
______werereportedbytheweatherstationinChicago.[originaltext]Onthe
Howmanycarsaretowedfromthestreetseachyear?[br][originaltext]One
Howmanycarsaretowedfromthestreetseachyear?[originaltext]Oneofth
随机试题
Iwasannoyedbymyfriendwhocamelateforourappointmentbutdidnotbother
"Holmes!"Iwhispered."Whatonearthareyoudoinginthisdisgustingplace?"A、
[originaltext]M:IamsorelievedIjustfinishedthestoryIwasworkingonfo
A.1/5小于a小于1 B.a大于1或a小于1/5 C.1/5≤a≤1 D
初始地籍调查技术总结概述的内容不包括( )。A.调查区概况 B.经验教训的总
A.自律性膀胱 B.无张力性膀胱 C.无抑制性膀胱 D.反射性膀胱 E.
能够从上述资料中推出的是:A.2016年A市气候调节价值年值超过700亿元
香附应A.燎去毛 B.刷去毛 C.烫去毛 D.挖去毛 E.撞去毛
A.苯海拉明 B.西咪替丁 C.组胺 D.阿司咪唑 E.昂丹司琼可引起乳
(2015年真题)某公司销售人员与财务人员常常发生冲突。销售人员指责财务人员用烦
最新回复
(
0
)