英语"It's been a long time."这句话不太理解

英语"It's been a long time."这句话不太理解 It\'s been a long time.这句话应该是被动语态吧?能不能用一些简单的句子讲解一下被动语态呢? It's a long time since还是It has been a long time since Hi Mary It's been a long time .语法填空 找一首歌.歌词里有一句“it s been a too long time” It's a long time since it raimed last time帮忙翻译下这句话, it is been a long time这句话有语法上错误吗? it has been the case for a long time that...这句话正确吗? It's+been++a+long+time.been在这里起什么作用?为什么要用been It's been a long 找一首英文歌 第一句是it s been a long long time It's been so long 这句话有语法错误码?