can'thelpdoing和can'thelpbutdo的区别如题,另外想问的是,but后面到底是跟动词不定式还是现在分词?为什么有的时候是动名词比如：Ilikenothingbutswiming有时却是动词不定式比如：Therewasnothingt

　　can'thelpdoing和can'thelpbutdo的区别

　　如题,另外想问的是,but后面到底是跟动词不定式还是现在分词?为什么有的时候是动名词比如：Ilikenothingbutswiming有时却是动词不定式比如：Therewasnothingtodobut