词典释义：
a part that is added to something to enlarge or prolong it; a continuation
延长部分；扩大部分；附加部分
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the railway's southern extension .铁路向南延伸的部分。
a room or set of rooms added to an existing building
（建筑物的）扩建部分。
[mass noun]the action or process of becoming or making something larger
扩大，扩展
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the extension of the President's powers .总统权力的扩大。
an application of an existing system or activity to a new area
（现有体系或活动范围的）延伸
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direct marketing is an extension of telephone selling .直销是电话销售的一种延伸。
an increase in the length of time given to someone to hold office, complete a project, or fulfil an obligation
（任期等的）延长。
〈主英〉 （在特殊情况下给予持证营业场所的）延时售酒许可。
【计算机】 （文件的）扩展名。
(
（编入头发中以使长发发型更长的）假发丝。
(亦作
（能让电器在离固定插座若干距离的地方使用的导线的）延长线。
a subsidiary telephone on the same line as the main one
（和主机共用一条线路的）电话分机。
a subsidiary telephone in a set of offices or similar building, on a line leading from the main switchboard but having its own additional number
（接在电话交换台线路上的有分机号码的）电话分机。
[usu. as modifier]extramural instruction by a university or college
（大学附设部的）业余进修教育
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a postgraduate extension course .对校外研究生开设的进修课程。
[mass noun]the action of moving a limb from a bent to a straight position
（四肢的）伸展；伸直
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seizures with sudden rigid extension of the limbs .四肢突然变得僵直的癫痫发作。
the muscle action controlling this
（肌肉的）伸，伸展
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triceps extension .三头肌的伸展。
【芭蕾】 （舞蹈者将腿举到腰部以上的）伸腿（能力）
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she has amazing extension 她的伸腿能力让人惊讶
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[count noun]
he could perform 180-degree extensions .他可以做１８０度的伸腿动作。
【医】 牵伸（术）。
the lengthening of a horse's stride at a particular pace
（马的）步幅的加大。
【逻】 外延。常与<Bold>INTENSION </Bold>相对。
【物理，哲】 广延（性）
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nature, for Descartes, was pure extension in space .对于笛卡儿来说，自然界就是纯粹的空间广延。
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by extension taking the same line of argument further 乃至，推而广之the study shows how television and, by extension, the media, alter political relationships . 研究表明 电视，乃至整个媒体是如何改变政治关系的
"late Middle English： from late Latin
