audience是个集合名词
形式为单数,但意义可以用为单数或复数
这类集合名词包括family,team,class,等,其用法特点为：若视为整体,表示单数意义；若考虑其个体成员,表示复数意义.
例句
His family is large.他的家是个大家庭.
His family are all waiting for him.他的一家人都在等他.
This class consists of 45 pupils.这个班由45个学生组成.
This class are reading English now.这个班的学生在读英语.