He usually plays sports (on weekends)对括号内提问

提问：When does he usually play sports？

He usually plays sports on weekends意思是他通常周末参加体育活动。

根据句意，此句为含有第三人称单数的一般现在时，提问时间用when，主语是he，助动词用does，原句动词 plays 还原为play。