optional 是一个英语单词，形容词，作形容词时意思是“可选择的，随意的”。
专业释义英英释义
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选项课 - 引用次数：61
The optional course of volleyball is one of the courses opened in general colleges.
排球选项课是普通高校普遍开设的体育课程教学内容之一。
参考来源 - 山西省普通高校排球选项课的教学研究 -
可选 - 引用次数：12
The study reveals that nine generic elements constitute the Generic Structural Potential (GSP) of LJAA, of which the Purpose of Study is the sole obligatory element and the rest remain optional.
研究揭示，语言学期刊文章摘要的体裁结构潜势包括九个成分。 其中研究目的是必要成分，其余为可选成分。
参考来源 - 从功能语言学角度对摘要的体裁分析 -
任选的任选（的）
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选择性选项任选
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任选的可选的
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柯林斯英汉双解大词典
optional /ˈɒpʃənəl/ CET4 TEM4
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1.
ADJ If something is optional, you can choose whether or not you do it or have it. 可选择的
例：Sex education is a sensitive area for some parents, and thus it should remain optional.
性教育对一些家长来说是个敏感的话题，因此应该还是非强制性的。
双语例句原声例句权威例句
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Certain courses are compulsory, others are optional.
某些课程是必修的，其他是选修的。
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Optional extras include cooking classes at a top restaurant.
可选的额外之物包括一家高级餐馆的烹饪课程。
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The course consists of ten core modules and five optional modules.
这门课程包括十个必修单元和五个选修单元。
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She points out that many foreign graduates ask to stay for what is called optional practical training.
VOA: special.2009.07.02
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I want to just go over the requirements of the course that really are required, not the optional piece, just so that you understand what my purpose is pedagogically.
我只想跟大家回顾一下,这门课程的必须要求，并非可以自由选择的,这样你们会理解我的目的何在。
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So they're optional, but they're very, very, very highly encouraged that you do these, because this is going to give you practice for the types of problems that are going to be on the exam.
虽然它们是选做的，但是它们非常非常，非常值得你们去做，因为这对你们来说是一次训练,是用来熟悉考试题型的。
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