单词	focal ratio
释义	focal ratio noun : f-number Example Sentences Recent Examples on the Web An eyepiece changes the focal ratio of your telescope, thus changing the magnification. Cameron Johnson, Popular Mechanics, 10 Nov. 2020 Word History First Known Use 1883, in the meaning defined above
随便看	call center call change call down call duck call for call forth call forwarding call game call girl call girls call house call houses call in call in on call in question call in sick call into doubt call into play call into question call it a day call it a night call it an early night call it like one sees it call it quits call it/them like one sees it/them

英语词典包含469781条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。