Sentence:  General Jones was fresh from a long series of bridge burnings , including the long bridge at Fairmont , and , after seeing a great drove of horses and cattle he had collected safely across the bridge , he sent his men to <WSD>work</WSD> piling combustibles in and around it . 
Meaning of the word marked with <WSD> tags:  exert oneself by doing mental or physical work for a purpose or out of necessity