if there had not been a hard layer of rock beneath

发布时间：2021-02-28 04:12:26

if there had not been a hard layer of rock beneath the soil,they would have pleted the job in a few hours.这句话为什么要用过去完成时呢?为什么不用一般过去式呢?改成这样 if there were not a hard layer of rock beneath the soil,the

网友回答

虚拟语气,条件句要往后推一个时态,一般过去式变为过去完成时.这里是语法问题,跟语义关系不大.
以上问题属网友观点，不代表本站立场，仅供参考！