"The book would not have been read"

Translation: Kitabu kisingesomwa

[vnClJTUL]

Is it okay to use the conditional tense in isolation like this? The notes make no mention of using -nge- or -ngali- on their own as the apodosis of a nonexistent condition.

[vitoreiji]

I would have expected -ngali- here instead of -nge- because of the "would [not] have" part. Why is that not the case?