A：if; Whether
B：whether; Whether
C：if; That
D：if; If
我快乐，是因为我喜欢幻想，所有的石头上都开满了花果，________，幻想已知如此丰茂，我有什么理由感到沉重和悲哀呢?
— Would you like to do it at all?
— I'd love to, but the question is _____it is worth doing.
