'No; he has a latchkey, and he let himself in.'

'实在不知道。他有一把弹簧匙，他自己会开门进来。'

There was a spring lock on the door.

门有一把弹簧。

That latch is a bit stubborn, but I'll take care of it.

那道弹簧处理 但我会处理好。

Mrs. Saunders, the caretaker, was about to leave, but she had no hesitation in admitting us, for the door shut with a spring lock, and Holmes promised to see that all was safe before we left.

看门人桑德斯夫人正要离开， 但她毫不犹豫地接纳了我们， 因为门是用弹簧关， 福尔摩斯答应在我们离开之前确保一切安全。