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 The names of specific people have been replaced by generic words (e.g., PersonX, PersonY, PersonZ).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 Head is capable of the Tail or not. Being capable of something includes general capabilities, such as a human is capable of thinking and reasoning or drinking coffee. It also includes specialized capabilities such as a surgeon is capable of operating on a patient. 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.

Q: Head: tenor<sep>Tail: add variety to singing group

A: Yes
****
Q: Head: PersonX accomplishes PersonY's work<sep>Tail: is upset

A: No
****
Q: Head: referee<sep>Tail: time race

A:
Yes
****