是how great fun还是what great fun

是how great fun还是what great fun what a great fun/what great fun为什么不可以用how great fun 英语的fun可数吗?是What a great fun it is!还是What great fun it is! 是have a great fun还是have great fun啊 great fun fun是名词 great fun what great fun\what a great fun.哪个对 为什么是what great fun it is!而不是what a great fun it is! great fun 还是 great funny 为什么 It was great fun!还是：it sounds great fun? such a great fun还是such great fun great fun 和a great fun