Did 和事件研究法等确实有别，但是为了方便而且也不歧义，下面就只说 did 了。 这当然是极好的，did 方法从获得诺贝尔经济学奖到本科生都能应用的时间并不长。这点也和工具变量法当. 真的很多人把精神分裂和人格分裂搞混，但二者实际上很大差别。精神分裂症英文名叫 schizophrenia ，俗称的人格分裂症或者说分离性身份识别障碍的英文全称 dissociative identity. Not only 后的句子引起半倒装，but also后的句子使用陈述句语序。 not only did he help his sister with her homework, but also he cooked a meal for his mother.
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