Sentence:  A little later the district attorney woke up , emerged from under the couch , looked at his watch , and <WSD>realized</WSD> he had an engagement that very hour to address a meeting of the Culture Forum on `` The Civic Spirit of the Southland '' , in the Byzantine room of the hotel where his wife , as president of the forum , was to preside . 
Meaning of the word marked with <WSD> tags:  be fully aware or cognizant of