Hi Zhang - it is a formula in French.
Something + (adjective) -> Quelque chose de/d' + _________________ (beau, amusant, merveilleux, triste)
Someone + (adjective) -> Quelqu'un de/d' + __________________ (charmant, sympa, intelligent, gentil)
It's hard to explain, as it's just one of those expressions that doesn't translate word for word into English. I would recommend just knowing the formula and not worrying too much about the individual components of the expression.