channel noun ⇨channel (a TV channel)⇨ditch (drainage channels)⇨medium (a channel of communication)
channel
noun
channel ♦︎ station ♦︎ network ♦︎ frequencyThese are all words for television and radio companies, the shows they broadcast, or the radio waves used for broadcasting them.这些词均表示电视台或电台、电视或广播节目、频道或波段等。PATTERNS AND COLLOCATIONS 句型和搭配◆a television channel / station / network◆a radio station / network / frequency◆to tune to a channel / station / frequency◆to watch a channel / station◆to change / switch channels / stations■channel [countable] a television company and the shows it broadcasts; a band of radio waves used for broadcasting television or radio shows电视公司；电视节目；（电视或广播的）频道，波段◆What's on Channel 4 tonight?第4台今晚放什么节目？◆a movie / sports channel电影台；体育台◆terrestrial / satellite / cable / digital channels地面／卫星／有线／数字频道■station [countable] (often in compounds常构成复合词) a radio or television company and the shows it broadcasts电台；电视台；（广播或电视）节目◆a local radio / TV station地方广播电台／电视台◆He tuned to another station.他换了一个台。■network [countable] a group of radio or television stations in different places that are connected and that broadcast the same shows at the same time广播网；电视网◆the four big US television networks美国四大电视网■frequency / /ˈfriːkwənsi/ / [countable, uncountable] (technical术语) the number of radio waves for every second of a radio signal频率（无线电信号每秒电波数）◆There are only a limited number of broadcasting frequencies.只有数量有限的广播频率。◆a frequency band频带
ditch
noun
ditch ♦︎ trench ♦︎ channel ♦︎ gully ♦︎ moat ♦︎ furrowThese are all words for a passage in the ground which water can flow through.这些词均表示用来排水的沟渠。PATTERNS AND COLLOCATIONS 句型和搭配◆an open ditch / trench / channel / gully◆a deep ditch / trench / channel / gully / moat / furrow◆a shallow ditch / trench / channel / gully / furrow◆a wide ditch / trench / channel / gully / moat◆a narrow trench / channel / gully◆to dig a ditch / trench / channel / moat◆a ditch / trench / channel / gully runs down / along sth■ditch [countable] a long hole dug along the side of a field or road, to hold or take away water（田地或路旁的）沟，渠◆The car went out of control and plunged into a ditch.那辆汽车失去控制，冲进沟里去了。◆Farm drainage ditches ensure that water runs directly into streams.农地里的排水沟确保了水能够直接流入河溪。■trench [countable] a long deep hole dug in the ground, for example for carrying away water（在地里开挖的）沟，渠◆They are digging a trench to hold a water pipe which will divert water from the river.他们正在挖一条沟，用来埋水管引流河水。ⓘ A trench is also a long deep hole dug in the ground in which soldiers can be protected from enemy attacks (for example in northern France and Belgium in the First World War). * trench还可指战壕◆He spoke movingly of his time in the trenches during the First World War.他生动地讲述了自己在第一次世界大战期间的战壕生活。◆They had not been prepared for the horrors of trench warfare.他们对堑壕战的恐怖经历还没有思想准备。■channel [countable] a passage that water can flow along, especially in the ground or on the bottom of a river水渠；沟渠；河槽◆A channel is being dug to divert the river.人们正在挖一条沟渠，以便引流河水。■gully ( gulley) [countable] a small, narrow passage which water flows along, usually formed by a stream or by rain; a deep ditch溪谷；冲沟；沟壑◆The slope was still awash with water spilling down deep gullies.那山坡依旧深壑遍布，溪水漫流。■moat [countable] a deep wide channel that was dug around a castle and filled with water to make it more difficult for enemies to attack护城河◆The castle was ringed by a moat spanned by a wooden drawbridge.城堡四周环绕着一条架有木吊桥的护城河。■furrow /ˈfʌrəʊ; NAmEˈfɜːroʊ/ [countable] a long narrow cut in the ground, especially one made by a plough for planting seeds in犁沟；沟；车辙◆Water lay in the furrows of the ploughed fields.在耕过的田野上，一道道犁沟积满了水。◆Truck wheels had dug furrows in the tracks.卡车车轮在小路上留下一道道车辙。
medium
noun
medium ♦︎ vehicle ♦︎ channel ♦︎ catalyst ♦︎ instrumentThese are all words for a person, thing or system that makes sth happen or allows sth to happen.这些词均表示使某事得以发生的手段、工具、方法。PATTERNS AND COLLOCATIONS 句型和搭配◆a medium / a vehicle / a channel / a catalyst / an instrument of / for sth◆the / a / an main / important / major / effective medium / vehicle / channel / catalyst / instrument◆a powerful medium / vehicle / catalyst / instrument◆a useful medium / vehicle / channel / catalyst / instrument◆the ideal / perfect medium / vehicle / instrument◆a key / great catalyst / instrument◆(a / an / the) appropriate / proper / right medium / vehicle / channels◆(a) political vehicle / channels / catalyst / instrument◆a medium / a vehicle / channels / an instrument of communication / expression◆to see / use sb / sth as a medium / a vehicle / a catalyst / an instrument◆to regard sb / sth as a medium / a vehicle / an instrument■medium(pluralmedia) [countable] (ratherformal) a way of communicating information or ideas to people（传播信息或思想的）媒介，手段，方法◆The internet is the modern medium of communication.互联网是现代传媒。◆The classes look at various electronic and audio-visual media.这些课会探讨各种电子和视听媒体。◆English is the medium of instruction(= the language used to teach other subjects).授课语言是英语。■vehicle [countable] (ratherformal) something that can be used to express your ideas or feelings or as a way of achieving sth（表达思想或感情，或达到目的的）手段，工具◆Art may be used as a vehicle for propaganda.艺术可用作政治宣传的工具。◆The play is an ideal vehicle for her talents.这部戏是她施展才华的理想机会。■channel [countable] ( channels [plural]) a method or system that people use to get information, to communicate, or to send sth somewhere; a way of expressing ideas and feelings途径；渠道；（表达思想和感情的）方式，手段◆Complaints must be made through the proper channels.投诉必须通过正当途径进行。◆The company has worldwide distribution channels.这家公司拥有遍布全世界的经销网络。◆Music is a great channel for releasing your emotions.音乐是宣泄情感的好方法。NOTE辨析 Vehicle or channel?Channel is used especially to talk about a method or system used to give information, or to direct feelings and ideas, that might otherwise become dangerous or difficult to deal with. Vehicle is used more to talk about a way of getting creative and political ideas or other beliefs across to the general public. * channel尤指用以传递信息的途径或体系，或是调节感情和思想的方法－若不加以调节，这些感情和思想有可能变得危险或难以处理。vehicle较多指将创造性的思想、政治理念或其他信仰传达给大众的手段、工具。■catalyst / /ˈkætəlɪst/ / [countable] (ratherformal) a person or thing that causes a change促使变化的人；引发变化的因素◆I see my role as being a catalyst for change.我认为我的作用是促成变革。◆The riots were later seen as the catalyst for the new political developments.这些骚乱后来被视为新的政治发展的催化剂。■instrument [countable] (formal) something that is used by sb in order to achieve sth; a person or thing that makes sth happen促成某事的人（或事物）；手段◆The law is not the best instrument for dealing with family matters.法律并非处理家庭问题的最佳手段。◆Financial aid can become an instrument of control rather than a support.财政援助有时会成为实施操控的手段，而非单纯的支持。