When we find (time + se, raha hounga, rhi houngi, rhe honge) at the end any Hindi sentence, we call them future perfect continuous tense and as a helping or auxiliary verb we use /will have been + V1 + ing ), and to describe (time se) we use for or since. 

Affirmative Sentence Structure

Subject + will have been + V1_ing + for/since + time duration/exact time.

Negative Sentence Structure

Subject + will have NOT been + V1_ing + for/since + time duration/exact time.

Interrogative Sentence Structure

when sentences start with KYA

Will + Subject + have been + V1_ing + for/since + time duration/exact time?

WH + Will + Subject + have been + V1_ing + for/since + time duration/exact time?

Interrogative & Negative Sentence Structure

when sentences start with KYA

Will + Subject + have NOT been + V1_ing + for/since + time duration/exact time?

WH + Will + Subject + have NOT  been + V1_ing + for/since + time duration/exact time?