Non lo sapevo che non riuscivi a cantare.

English Translation

I didn’t know you couldn’t sing.

(I didn’t know you couldn’t sing) I have come across this type of sentence where the second verb (in this case, riuscivi) is in the past subjunctive rather than the imperfect. (Non avevo idea che non sapessi nuotare.) There seems to be an exception when the second half is factual rather than supposition, but is it more narrowly confined to the use of the verb sapere in the first half?


I believe that the nuance is identical to the one in French.

imperfect = emphasis on factuality
subjunctive = emphasis on surprise

And, as in French, the imperfect tends to gain ground in practice as native usage and mastery of the past subjunctive tend to disappear nowadays.