The file will have an exclamation mark to the left which demotes iTunes doesn't know it's location. Attempting to play will give you a message that it's missing and the option to find it. When you navigate and find the song, it should ask you if you want to add the others too.

"If it turns out that President Barack Obama can make a deal with the most intransigent, hard-line, unreasonable, totalitarian mullahs in the world but not with Republicans? Maybe he’s not the problem."