(1) i came here, when she sited in the chair (2) when i came here, she sited in the chair (3) she was sitting in the chair, when i came here (4) when she was sitting in the chair, i came here
其实我的语法很烂,上百度和看了薄冰总结了些愚见~用手机不方便所以略写了。楼主的2,4的逗号和用法都是没有问题的,薄冰上也有类似的用法,表达的都是同时发生,相当于一…就…的句型。而1,3的逗号我不清楚,感觉多余,不用也可以。然后百度上没有这个句型,按照意思我想楼主应该想表达的是之前就…了,但是应该是:i came here when she had sited in the chair,百度上只有这样用才能表达,薄冰里我没发现~求大牛~