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	melon melon aphid melon apple melon baller melon beetle melon cactus melon fly melon foot melon fruit melon hole melon loco melon louse melon pear melon pink melon seed melon shell melon tree melon yellow melongena melongene melonist melonite melonry melons melonworm

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