Undergo surgery has a sub-event of you learn something. Party does not have a sub-event of push power button. Party has a sub-event of drink beer. Celebrate does not have a sub-event of push power button. Watch tv has a sub-event of you learn something. Have friend over has a sub-event of party. Celebrate has a sub-event of party. Undergo surgery has a sub-event of look at art. Celebrate does not have a sub-event of whatever be inside will fall out. Drink beer has a sub-event of watch tv. Drive truck has a sub-event of look at art.
Celebrate does not have a sub-event of drink beer.