activity (of a person, organization, animal, volcano, etc.); action; operation
activity (esp. energetic or successful); great efforts; active participation
ボランティア活動に参加した。
I participated in volunteer activities.
クラブ活動は週三回あります。
Club activities are held three times a week.
彼女の活動範囲はとても広い。
Her range of activities is very wide.