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	plot's elm plotinian Plotinism plotinisms Plotinist plotinists Plotinus plotless plotlessness plotlessnesses plotline plotlines plotosid Plotosidae Plotosus plots Plott hound plottage plottages plotted plotter plottered plottering plotters plottier

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