小明看到鸡蛋浮在盐水面上，如图。他沿杯壁缓慢加入清水使鸡蛋下沉。在此过程中，鸡蛋受到的浮力F随时间t的变化图像可能是()。
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A. being stopped
B. were fixing
C. were fixed
D. fixed

A. done
B. having done
C. having been done
D. being done

A. step across
B. step out onto
C. step along
D. step on

A. filling
B. full of
C. filled
D. was filled