On 9 December, James Joyce experienced one of those coincidences which affected him () at the time and which later became material for his books.

A. inadequately

B. systematically

C. profoundly

D. simultaneously

下图是某地区潜水等水位线图，A、B两点水平距离为50m，图中的数字单位为m，试确定

简述潜水与河水间的补排关系