It is the third time that i have been in Beijing.帮忙分析下这句话的语法结构和时态,为什么用have been
问题描述：
It is the third time that i have been in Beijing.帮忙分析下这句话的语法结构和时态,为什么用have been
答
It is the first / second / third time.that…是一种固定结构
这一结构中的从句部分,用现在完成时