We have fun ---- English .

We have fun ____ English .A. to use B. using C. use D. used为什么选D请详解,并翻译这句话,谢谢.这道题我看错答案了，所以我会了，呵呵。麻烦帮我看一下下面这道题There are a lot of ____ things for young people to do here .A. funny B.fun C. funning为什么选A不选B，请详解，谢谢。