Sentence:  Marty <WSD>knew</WSD> how the Union soldiers must have felt at Chancellorsville and Antietam and Gettysburg when the ragged gray ranks charged at them , screaming the wild banshee howl they called the Rebel yell . 
Meaning of the word marked with <WSD> tags:  be cognizant or aware of a fact or a specific piece of information; possess knowledge or information about