doing还是step？
Steep，表示"台阶，步骤"。 Step to doing表示"做...的步骤"。本质上，后面的to doing是做step的定语，并且to是介词不是动词的不定式，所以应该用to doing。
There are only a few steps to doing the experiment.
So the first step to doing that is I want to just generalize our results.
类似的的还有，the key to the door，the answer to the question。
当然有时候，我们也会看到这样的短语，the first step to do，表示"第一步将要去做的事"。 to do表示将来。
相关短语, 如下:
Take steps to do 采取措施做...
= Take actions/ measures to do
