In this task, you are given two phrases: Head and Tail, separated with <sep>. The Head and the Tail events are short phrases possibly involving participants. The names of specific people have been replaced by generic words (e.g., PersonX, PersonY, PersonZ). PersonX is always the subject of the event. You have to determine whether The Tail is the reason for the Head or not. The reason provides a post-fact explanation of the cause of an event. For example, why one has to walk could be explained by a car has broken down. Classify your answers into "Yes" and "No". The phrase may also contain "___", a placeholder that can be an object, a person, and/or an action.

Head: PersonX accepts the invitation<sep>Tail: to go
No

Head: PersonX accepts PersonY invitation<sep>Tail: PersonX buys a gift for PersonY
No

Head: go on vacation<sep>Tail: you're tired

Yes