Relevant to this construction, our Italian tutor said that in Italy you would never say something like "puoi passare il sale" or "ci puoi guidare a teatro" in order to ask someone to do something. She said in Italian, you would only use "puoi" when you truly mean to ask "are you physically capable of doing this." She said instead you would say something like "mi passi il sale?" or "passami il sale, per favore." Does anyone with more experience know if that sounds reasonable?
So I answer "Can you ask how much it costs" without a question mark because it is never, ever deemed necessary for DL translation, and I can only assume that's why my answer has been considered wrong. Thanks DL for suddenly getting all serious about English punctuation without telling me.
And here we are, 8 months later and we are still being told 'Can you ask how much it's' Just proves that there is an exception to every computer based rule. The thing is that in other places in DL we are told that the 'it' is understood, and if it isn't a clitic is used. Certainly, in normal English conversation the 'it' is understood between the two parties who must have been discussing the object to have come to this point in the conversation. Just like there is a yawning chasm between english speakers who think they know italian, there is a similar void between italians who think they know english
Costare is an intransitive verb and as such cannot take a direct object. “Lo” is a direct object pronoun, yes meaning it or he but cannot be used in this position as a direct object. You are understandably trying to use it as a subject, and as you said “IT” is implied. There are words for “IT” As a subject that apparently are no longer used. I learned them when I studied Italian actually decades ago, and they were on their way out even then. The words are: Esso/essa singular and Essi/esse plural. Since I learned them I wondered where they went to and apparently they are used in literature and regionally in some parts of Italy. Just to blow your mind a little more there are two other words for “he” and “she”; they are egli and ella. Here is an overview: https://www.thoughtco.com/forgotten-italian-subject-pronouns-2011380
Redundancy. "Potere" is a modal verb. Verbs like can, must, want, etc are usually linked to a second verb. This following verb is almost always in the infinitive. "Puoi" is already in the second person form and gives you, "Can you…". "Chiedi" would give you, "Can you you ask…" The following verb must then be in its infinitive form. In this case, "Puoi chiedere…"
"Puoi chiudere la porta?"
You'll see this pattern everywhere, so it's important you understand it. "Volere," "potere," and "dovere" are the three most common. Remember, the modal verb takes the desired tense/person and the following verb is in the infinitive. Puoi capire cosa ti sto dicendo?