optional 英式发音['ɒpʃ(ə)n(ə)l]美式发音['ɑpʃənl]
optional基本解释
adj,可选择的,随意的,同近
optional相关例句和用法
three optional courses.三门选修课
optional英英释义
可选择的,随意的英释adjadjif something is optional, you do not have to do it or use it, but you can choose to if you want to
optional短语
optional course,选修课,选修课程.短语