Sentence:  So , for happy years , Helva scooted around in her shell with her classmates , <WSD>playing</WSD> such games as Stall , Power-Seek , studying her lessons in trajectory , propulsion techniques , computation , logistics , mental hygiene , basic alien psychology , philology , space history , law , traffic , codes : all the et ceteras that eventually became compounded into a reasoning , logical , informed citizen . 
Meaning of the word marked with <WSD> tags:  participate in games or sport