no saber trigger subjunctive?

Question

No sabemos si podrán arreglar el grifo.We don't know if they will be able to fix the tap.
does saber in the negative trigger the subjunctive?the above example uses poder in the simple future
thanks julie

Accepted Answer

Hola Julie
No saber que / si doesn't "normally" trigger the subjunctive. You are declaring what you don't know, so it's seen as a truth:

Ella no sabía que su novio era muy celoso.
She didn't know her boyfriend was very jelous.
No sé si iré al cine después.
I am not sure if I will go to the cinema later.

However, you may see it using the subjunctive if the speaker somehow feels a "rejection, disbelief" about that information. So you may see or hear something like:

Yo no sabía que tuviéramos que rellenar un formulario.
I didn't know we had to fill in a form.

The speaker could have used the indicative here as well "que teníamos que..." but, by using the subjunctive instead, they're presenting that "fact" as something they reject somehow, don't feel confortable with and they detatch themselves from that truth. 
I hope it clarifies it. 
Saludos
Inma