单选题 The young mother tried her best to keep her temper, but in the end her patience ran ______.

【正确答案】 B
【答案解析】[分析] 此题考查动词短语。run off“逃跑，(使)流出”；run out(of)“被用完，被耗尽”； run over“溢出，满出”；run away“逃跑”。