請問있다和없다其實是動詞還是形容詞??

基本上間接引用句的使用方法：

１．動詞用 ~느냐고
例如：가요? =>가느냐고２．形容詞用 ~[前面的一個字有收音用]으냐고
/~[前面的一個字沒收音用]냐고
例如：[有收音]좋아요? => 좋으냐고~
例如：[沒收音]예뻐요? => 예쁘냐고~但以上的使用方法也有例外：

例如：있다和없다是形容詞，但在間接引用時會用~느냐고．
있어요? => 있느냐고~
없어요? => 없느냐고~

例如：길다是有收音形容詞，但在間接引用時會用~냐고，
而不會用~으냐고．
길어요? => 기냐고~學習韓文除了一大堆語法要學習，還需要學習那一大堆的例外．
真的少一點恆心也不可以啊！加油吧！

it can be used as both VERB and ADJECTIVE

when used as VERB, it means
-the location when attached with -에 to present
eg. 지금 집에 있다. I am at home now.
-the state somebody being there
eg. 가만히 있어라! Just stay there!

when used as ADJECTIVE, it means
-the presence/existence/possession of something
eg. 이 세상에 귀신이 있다고 믿는다. I believe ghosts do exist.

TO answer your anther question
it should be attached with -느냐고 or simply abbreviated as -냐고 to do the reported speech for question
eg. 지근 집에 있냐고 했다.

있다和없다→存在詞
間接引用: 있느냐고