1.(拉屎) defecate; relieve the bowels; have a bowel movement 短语和例子 大便不通 (suffer from) constipation; 大便不正常 irregular bowel movement; 大便干燥 (motions)be hard and dry; 大便四次 have four motions2.(屎) stool; human excrement; faeces 短语和例子 去化验大便 have one's stool examined