It's aru followed by nda, which is the same as no da or no desu. It's used after the plain form of a verb, usually when providing some kind of explanation or making a point.
Postby community.japanese » June 15th, 2013 9:36 am
joaofilipepereiracosta5756-san, マイケルsan, thank you for the help, マイケルsan The sentence would be でも、ぼうけんに でるまえに、きみに いくつか しつもんが あるんだ。 Probably here, this speaker is saying like "Actually, I've got some questions...." or "To be honest, I have to...." instead of simple "I've got some questions...." sentence.