sentence: I tried to install a bird perch bar into my bird's cage, but struggled to get it in due to the 
complete: bar being too wide.

sentence: The man took the stairwell to the third floor instead of the elevator because the 
complete: stairwell was clear.

sentence: Laura was bitten and had their blood sucked by Felicia after they let them into their house. 
complete:
Felicia  was a vampire.