before and after comparison 前后对比

例句：

对照组治疗前后对比无显著性差异。

Compared with before treatment, control group were insignificant differences.

前后对比分析法在战略环境评价中应用初探

Application of before and after comparison methods to strategic environmental assessment

运用微探头超声检查食管下段静脉结构的情况，进行治疗前后对比研究。

Esophageal vascular structures were examined with miniature ultrasonic probe.

成年难治性癫痫患者生活质量手术前后对比分析

Quality of life with the affection of operation in adults with epilepsy