f(x)'s Krystal and Sulli Q & A BTS video! F(X)雪莉及KRYSTAL的Q&A幕后花絮！

Check out the BTS video of f(x)'s maknaes Sulli and Krystal for Q and A.

快来看看f(x)忙内Krystal及雪莉拍摄Q&A时的幕后花絮吧！