Sentence:  It 's one thing to go without food when you 're occupied with some work or when you 're simply postponing a meal , but when you 're dependent on someone else and know that you can n't eat until he 's bedded down for the night , hunger can <WSD>be</WSD> a gnawing torture . 
Meaning of the word marked with <WSD> tags:  be identical to; be someone or something