Sentence:  When they got home Harold was grateful for the stillness in the apartment , and <WSD>thought</WSD> how , under different circumstances , they might have stayed on here , in these old-fashioned , high-ceilinged rooms that reminded him of the Irelands ' apartment in the East Eighties . 
Meaning of the word marked with <WSD> tags:  use or exercise the mind or one's power of reason in order to make inferences, decisions, or arrive at a solution or judgments