antecedent: adj.1.先行的，先前的。2.【逻辑学】假定的，前提的。3.【地质学；地理学】先成的。n.1.先例，前例。2.〔pl.〕经历，履历，学历。3.〔pl.〕祖先。4.【语法】先行词。5.【逻辑学】前提，前件。6.【数学】(比例的)前项〔如 a∶b 中的 a〕。短语和例子inquire into sb.' s antecedents 调查某人履历。 a man of shady
About 15 to 20 percent of patients who require treatment for perforation or bleeding will not have an antecedent history of ulcer pain . 为出血或穿孔而需治疗的病人中，约1520以往无溃疡疼痛的病史。
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About 15 to 20 percent of patients who require treatment for perforation or bleeding will not have an antecedent history of ulcer pain 为出血或穿孔而需治疗的病人中，约15 ? 20以往无溃疡疼痛的病史。
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About 15 to 20 percent of patients who require treatment for perforation or bleeding will not have an antecedent history of ulcer pain 为出血或穿孔而需治疗的病人中，约15 20以往无溃疡疼痛的病史。
