Translation:The shirt is under the pants.
No; κάτω is an adverb, not a preposition.
You can use it by itself with pronouns (κάτω του), I believe -- but not with nouns, where you need to add a preposition.
A bit like English "because of" or "due to" -- you can't say "The match was cancelled because the rain / due the rain"; you have to add a preposition to form a kind of compound preposition "because of, due to, κάτω από, πάνω σε, etc.".
The pronunciation of "παντελόνι" in the fast sound sample sounds like the 'ντ' is 'd', while in the slow sample the 'n' is clearly heard.
I understand that 'ντ' is sometimes pronounced as 'd', but I thought this was determined by the following letter, not by the speed of speaking. So, my question is: is ''ντ' often "slurred" into a 'd' sound, or is there a problem with the audio here.