3.had sb done sth(坏事) ， sb would never have done sth (好事)如果某人过去做了某件坏事，而不是去做某件好事，那么他永远不可能做某事(好事)
    例句：had the little scotch lad, ferguson, allowed the busy brain to go to sleep while he tended sheep on the hillside, instead of calculating the position of the stars by a string of beads, he would never have become a famous astronomer.

对以上几个虚拟语气的应用范文：group discussion googleif google had ignored the importance of group discussion, this high-tech company would never have achieved today's stunning success.(if sb had done sth, he would never have done sth)google, a once obscure, ailing / fragile company, would never have achieved today's stunning success, never have conquered so big a market share, if it had ignored the importance of group discussion.(sb would never have done sth , never have done sth , if sb had done sth)