It is a waste of time doing this这里为什么用doing而不用do?为什么?

It is a waste of time doing this这里为什么用doing而不用do?为什么? it is a waste of time doing还是to do 请问,It is a waste of time 后该用to do 还是 doing it is a waste of time doing接SB怎么接 it is no wonder to do sth接 It is a waste of money 后用to do还是 doing a waste of time后加TO DO还是DOING It's a waste of time doing sth. 有it is a waste of time doing sth 这种用法吗? 适当形式填空Stop doing that!It is a waste of time and ____________ THIS IS NO GOOD TALKING WITHOUT DOING ANYTHING为什么用THIS 不用IT it is more adj.to do than to do 在这里为什么不可以用doing? it is a waste of time to do 这个句子