Everyone had an application form in his hand,but no one knew whic_英语解答

Everyone had an application form in his hand,but no one knew which room (to send it to).请问括号里的部分做什么成分啊?另外逗号后边的整句话是什么结构?

人气：103 ℃　时间：2020-03-24 09:01:11

解答

括号里的是动词不定式做定语,修饰room
后面半句的意思是：但没人知道应当把它送到哪个房间.