标准灰板的反光率为 _( )_ 。夜景人物纪念照所用闪光灯指数(GN)为24,如果人物离相机距离为4米,拍摄时应选用的光圈为 ( )_ 。
No more having to buy expensive textbooks which you will only use for a year or two and then sell or _______ away.
You can _____ some bottles of wine, or some chocolates, or a bunch of flowers.
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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