过去完成时通常用在从句中,例如,She said ,“I has been to Shanghai twice.”这句吧,把它变成间接引语时,从句的现在完成时,就必须变成过去完成时.She said (that )she had been to Shanghai twice.所谓的对现在造成的影响就是说过去做的事影响到现在的情况,主要强调现在.例如,He has mastered two thousand words since he began to learn English.就是说过去开始学这个“学”对现在的影响是“掌握了二千个单词了”.
