al tocar al timbre

Question

in the sentence "al tocar el timbre,oyó una voz: ¡Pase!", where does al come from, "a el"?

Answer 1

"When he rang the doorbell, he heard a voice. Come in!"

Literally "On ringing the doorbell..." This sounds quite stiff and formal in English but I remember reading a post by our friend Lazarus saying that it sounds perfectly natural in Spanish. I think you can do this with any verb...

Al ver el accidente... (On seeing the accident - when I saw the accident)

Al encontrar las llaves... ( On finding the keys - When he found his keys)

....but I am not a native speaker so......