have fun (in) doing sth．开开心心做某事 have fun意为“过得快活”，后常接动词－ing形式，其前的介词in可以省略.相当于enjoy oneself，have a good time。如： The boys are going to have fun (in) drawing the pictures.have fun doing sth.跟have fun in doing sth.没什么区别,可以通用.更多的类似例子:have problems（in）doing sth．做某事有困难 problem后接动词－ing形式，其前的介词in可以省略。如： They had no problem（in）fixing the car．
