It was a scene that would stay forever in his mind: the father holding his son above the water, himself slowly（ ）in the lake, desperately awaiting rescue.
考查动词辨析。A选项overstepped“逾越；超越”；B选项overflowed“溢出”；C选项subjected“使遭受；使从属”；D选项submerged“淹没；沉浸”。句意：这一幕将永远停留在他心中：父亲托举儿子露出水面，自己却慢慢……于湖水中，绝望地等待救援。由关键信息above the water“在水面上”可以知道父亲的身体正淹没在水中。因此D选项符合题意。
