The waves ________ violently against the shore, people couldn't hear them crying for help.
句意：海浪猛烈击打着海岸，人们听不到有人在求救。考查独立主格结构。前后无连词，且逗号后为完整句子结构，所以可判断此处为独立主格结构，排除B、C、D。