Sentence:  His energy was prodigious ; <WSD>sometimes</WSD> he would be up before dawn , clad as a garbage collector and hurling pails into areaways to exasperate us , and thereafter would hurry to the Bronx Zoo to grimace at the lions and press cigar butts against their paws . 
Meaning of the word marked with <WSD> tags:  on certain occasions or in certain cases but not always; at other times for six months"