has increased 是现在完成时态。the number of visitors to the village of frinley 是主语 这句的意思是:为什么到frinley 村的游客的数量增加了。如果用is...increased 是被动语态,不合题意。如果用does 就更不行,因为increased 是过去分词。当然,这句也可以改成:Why does the number of visitors to the village of Frinley increase? 这些问题搞不懂是因为你对特殊疑问句结构没弄清:特殊疑问词(就是what, how,when,where 等)+一般疑问句。所以why has... 是why + 现在完成时的特殊疑问句Why has he stayed here for such a long time?. why does he often go there? 是一般现在时 what had he done before I arrived 是过去完成时 what did he do? 是一般过去时