I lost the key to the door.

我把门钥匙丢了。

youdao

I have mislaid my key to the door.

我不知道把门钥匙放到哪里了。

youdao

It was the key to the door that they locked for yesterday.

昨天他们寻找的是房门的钥匙。

youdao

And the degree to which you can have experiences where you are being intimate with the natural world, is part of that sort of key to open the door to those transcended experiences and to the spiritual nature.

你会有一些与自然亲密接触的经历,你能从这些经历中感悟到多少，决定着,你能否打开通往超验和,神性的门。

普林斯顿公开课 - 人性课程节选

Gone are the small gatherings at home and cheap keepsakes such as the 21st key to the door.

BBC: Why has everything become a costly milestone event?

"Stem cell research has the potential to act as the key which opens the door to many advances in our knowledge and our ability to treat some of the most heart-rending conditions that are presently untreatable, " said the Aberdeen South MP, who suffers from a genetic condition called Gaucher's disease which results in brittle bones.

BBC: MPs vote to extend embryo research

He has an agreement with the government to cooperate in exchange for a lighter sentence, but prosecutors can argue he's already won his "key to the jailhouse door" by testifying against Skilling.

FORBES: Caught In The Crossfire