Back when and Until now

Until now and back when are semantically related in earlier topic. In some cases you can use "Until now" instead an adverb phrase "Back when".

Until now adverb - Used in negative statement to describe a situation that has existed up to this point or up to the present time.

Back when and until now are semantically related in earlier topic. Sometimes you can use "Back when" instead an adverb phrase "Until now".