一道英语选择题，帮助，谢谢
why can't I swim as well as you?
But if you keep _______,you will be a swimming one day
A.practising to swim B.practise swimming C.practising swimming D.to practise swimming
哪位仁兄能告诉答案，还有原因，一定要告诉我原因啊，谢谢
参考答案:C
坚持做某事 keep doing
练习做某事 practise doing