单选题 Tom and Ben have ______ again and stop talking to each other.
A. fallen in B. fallen out
C. fallen through D. fallen up

【正确答案】 B
【答案解析】[解析] B项的fall out“起纠纷，争吵，结果”符合题意。fall in跌入；fall through落空，失败；fall up没有此短语。