我们可以看到admit, confess, deny, forget, recall, regret, remember 7个动词后接doing，相当于having done这个结构。

admit

When you are talking about finished actions, you can say having done/stolen/said etc.:

She admitted having stolen the money.

But it is not necessary to use having (done). You can also use the simple –ing form for finished actions:

She admitted stealing the money.

I now regret saying (or having said) what I said.

She admitted stealingthe bicycle/admitted having stolenthe bicycle.

她承认偷了自行车。

She admitted that she had stolen the bicycle. 她承认偷了自行车。

confess

如果是过去已经发生的事实（瞬间动词），可以用动词的现在分词形式即-ing，也可以用动词的现在分词完成式，即having pp。（例如）

The boy confessed to breaking the vase. 男孩子承认自己打碎了花瓶。

I must confess to having done some flagrant cheat.