._____ this experiment is not difficult .(为什么是to do 不是doing!

._____ this experiment is not difficult .(为什么是to do 不是doing! _____ this experiment is not difficult.A.Having done B.Being 是find difficult doing还是find difficult to do is difficult to do sth .还是to doing pay attention to为什么一定是doing,为什么不是do 1.This is not very difficult.______ can do it. this problem is not difficult.you can do it ( ). _____ sports is good for us.前面用To do还是Doing.为什么? I find this experiment is（）for us to do.A This is the way to do it.中的to可以去掉吗?或者把to去掉do变doing?为什么? This maths problem is rather difficult,but it is not _____ t 英语there is no need doing还是to do 答案给的是doing 为什么