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
27
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
YouwillhearabusinesspresentationaboutHigh-ImpactViralMarketingStrategi
Youwillhearaspeakergivingabriefintroductionaboutafamouscompany,
Thechildrenlinedupandwalkedout______.A、inplaceB、inconditionC、inorder
Afewyearsagoitwas(36)______tospeakofagenerationgap,adivisionb
患者,男性,45岁。搬抬重物后出现腰痛伴右下肢放射痛3天来院就诊,诊断为腰椎间盘
IT资源管理中的硬件配置管理,硬件经常被划分为各类配置项(Configurati
A.2:1 B.8:1 C.3:1 D.4:1 E.5:1新生儿颅部与面
患者男,28岁。右侧胸外伤后,出现呼吸困难、发绀,胸壁伤处可听见空气进出的声音。
获得批准的证券公司应当按照规定,向公司登记机关申请业务范围变更登记,向( )申
严重的不良反应不包括A.致残、致畸、致癌 B.造成器官损害 C.不良反应症状
最新回复
(
0
)