Girl in blue and white uniform doing cheers
A boy is performing in a marching band .
Girl in blue and white uniform doing cheers
A boy is performing in a marching band.
The subject is either a girl or a boy, not both.  The subject cannot be doing cheers and performing in a marching band simultaneously.
The subject is either a girl or a boy , not both . The subject can not be doing cheers and performing in a marching band simultaneously .