【正确答案】 C

【答案解析】解析：submerge v.浸没，淹没(如：He submerged his hands in warm water．Submarines can submerge very quickly．The river submerged large tracts of land．)。merge v.(使)结合，(使)合为一体。emerge vi．出现，涌现；(问题)冒出，(事实)暴露。cover vt．覆盖。