1. audience是集合名词，用作主语时，其谓语可用单数(视为整体)或复数(视为个体)。如：http://yingyu.chazidian.com The audience is [are] listening attentively. 听众都在聚精会神地听着。 The audience was [were] enjoying every minute of the performance. 观众对演出非常欣赏。 The audience is [are] always very excited by a wonderful goal. 一个精彩的进球总会使观众们非常激动。
2. 由于audience 是集合名词，所以an audience 不是指“一个观众”，而是指某一群观众、某一个场次观众、某一方面的观众等。如： She has never spoken to such a big audience before. 她以前从未向这么多人讲过话。 He loves holding forth on any subject once he has an audience. 不管是什么问题，只要有人听，他就爱大发议论。 同样地，audiences 也不是指“多个观众”，而是指多群观众，多个场次观众，多个方面的观众等。 Entertaining audiences is the purpose of movies. 娱乐观众是电影的目的。 The show had to be taken off because of poor audiences. 因观众太少而取消演出。 She has addressed audiences all over the country. 她曾向全国各地的听众演讲。 另外，audience作为集合名词，原则上不能用它表示个体，但every audience是例外，当要强调每一名观众时，可以这样用。如： The pianist made a conquest of every audience for which she played. 这位钢琴家以她的演奏征服了每一位听众。
3. 形容听(观)众人数之多或少，通常用big, large, huge, mass, vast, wide 以及small, thin等形容词修饰，但是不用many, few修饰。如： There was a large audience of young people at the pop concert. 流行音乐演奏会上有大量青年听众。 Her lecture had a crowded audience. 她的演讲挤满了听众。 The speaker had a small (thin) but attentive audience. 这位演讲者的听众不多(很少)，但很专心。(http://yingyu.chazidian.com) She felt nervous at having to sing before so large an audience [such a large audience]. 要在那么多观众面前唱歌她感到很紧张。
4.要具体表示观众的数量，可参考以下表达： There were at least three hundred people in the audience. 观众至少有300人。 The series has attracted an audience of more than 10 million. 这个系列片吸引了1,000多万观众收看。 An audience of millions watched the royal wedding on TV. 数以百万计的人们在电视上观看皇家婚礼。 不过，偶尔它也可直接受数字(通常为较大的数字)的修饰。如： Three thousand audience crowded the concert hall. 3,000名听众挤满了音乐大厅。