不承认做过某事 英语怎么说?

楼主说的对,admit doing sth 承认做某事,admit是及物动词.
admit to doing承认做某事admit是不及物动词
不承认做某事 sb doesn't admit doing sth.
拓展：admit及物动词 vt.
1.承认[+v-ing][+(that)][O2]
You must admit the task to be difficult.
你得承认这个任务是艰巨的.
We have to admit that he's a highly competent man.
我们必须承认他是个非常能干的人.
I admitted breaking the window.
我承认打破了窗子.
2.准许进入;准许...进入(或加入)[(+into/to)]
No one but ticket-holders was admitted.
只有持票者方可入内.
3.容许;可容纳
The theater admits 1000 people.
这剧院可容纳一千人.
不及物动词 vi.
1.承认[(+to)]
I must admit to feeling ashamed of my conduct.
我得承认因自己的行为而感到羞惭.
2.容许,有余地[(+of)]
This matter admits of no delay.
这事不容耽搁.
3.通向[(+to)]
祝学习愉快!