是who is in the park,此处who做主语,谓语用单数,例如:
1. His argument presupposes that it does not matter who is in power.他的论点前提是谁掌权都无关紧要。
2.Who is in the chair today?今天谁主持?3.This is an easy routine, designed for anyone who is unused to exercise.这是一套简单的固定动作,是为不常锻炼的人设计的。