Question

Read the sentence. lifting the heavy couch and moving it down the stairs by himself required a _____ effort. which word works best in this sentence? promethean herculean siren narcissistic

Answer 1

the answer to this question is herculean. Because hercules was a strong man and the definition means to require great strength or effort :) 

Answer 2

The answer to your question would be that the word that works best in the sentence is the following one: Herculean. That is, the sentence would be as follows: Lifting the heavy couch and moving it down the stairs by himself required a herculean effort.

Collins dictionary defines "herculean" as a quality which has to do with requiring extremely great strenght and effort.