Talking about the things in "sth of sth else" For example, about "parts of machines": there are different parts of different machines, each part is belonged to a machine. We may say 1. to ask about a part for the thing it's belonged to - Which/what machine is the thing the (a) part is belonged to? (Which forms of sentences can be used here to express such the question?) 2. sometimes it needs to talk it very generally without such as "machine", "belong", even "thing", for example, - One may need to know, for any part, what is that a part of? or, what is that it of? (Is this a simple, right, even good sentence in certain contexts?)