Spanish phrase
A menos que ~.
Meaning
Unless ___.
When to use it
Indicates a required condition is missing. Used to say that something will not proceed and often prompts the listener to supply what is needed.
Example dialogue
A menos que tengas la llave, no podemos entrar.
Unless you have the key, we can't get in.
Entonces la voy a buscar ahora.
Then I'll go get it now.