If I use google translator, sure there's a little problem on my language. As for your question, I am not good so because I am currently at the year of around 9-14... (I would not like to say the exact.) and I'm not a English speaking child...How good is your English?
2) Also, may I know what is the name of wood (mostly yes, wood) that hide the wire so the wire will not be visible. I mean the wood that mostly use in homes that cover the wire.
In the metric world, we call it 48 x 098. 48millimeters one way and 98millimeters the other. Yes it it 098.The wood framing can be called 2x4(2 by 4).
In Norway we are using drywalls a lot. And steel/metal studs. One thing the electrician is very careful about, is when wiring, he puts the cable as far in the middle in the stud as possible. Something like 22mm from the edge. That way, when the carpenter is putting on the plates, the screws do not enter the cable. That would result in a shortening, which is no good.I think the wood you are talking about goes as the 'wall'. It is called sheetrock, drywall, other names as well. You could probably also use plywood.
http://en.wikipedia.org/wiki/Drywall
The wires are in a flexible plastic pipe. At least they are in Norway.NEVER run wires through metal studs unless you've got the snap in insulators for the holes. Only common sense.
Get a copy of the NFPA-70 - even if old - and read through it.