Just as she was about to support the woman when a car came to her at fastspeed.这句话语法上有没有错误?

问题描述:

Just as she was about to support the woman when a car came to her at fastspeed.这句话语法上有没有错误?

是的,这是个并列句,中间的when 是并列连词(= just then),所以前面不能有从属连词just as
正确的为:
She was about to support the woman when a car came to her at fast speed.