I knocked but there was no one around.

我敲了门，但是没有人应门。

《牛津词典》

I knocked on the door but nobody answered.

我敲了门，但无人应答。

《牛津词典》

Carol answered the door as soon as I knocked.

我刚敲过门，卡罗尔就把门打开了。

《柯林斯英汉双解大词典》

Azalea Adair herself opened the door when I knocked.

VOA: special.2009.01.17

In the case of Nimes, N-I-M-E-S, which was largely a Protestant town, they knocked down the wall so the Protestants of Nimes could not defend themselves against this all-conquering Catholic monarch.

以尼姆为例,那儿曾经是一座新教徒的城市,但统治者们拆毁了围墙,所以新教徒们再也无法对抗,所向无敌的天主教统治者了

耶鲁公开课 - 欧洲文明课程节选

The others in the room grew silent. I had knocked down one of their warriors with only my hand.

VOA: special.2010.07.17

He's just going to be the big dude I knocked out in Germany.

BBC: Haye targets 'B-level' Klitschko

Two days later Mitch and I were jumping straw bales, without any reins or stirrups, when I fell off and hit my head so hard I knocked myself out.

WSJ: A Horse-Crazy Girl's Separation Vacation

"He told me I needed an operation to remove the disc because if I knocked it even during a mundane activity around the house it could kill me, " said Thompson.

BBC: Injury forces Thompson to retire