1. 必须用复数的情形

有的集合名词作主语时，其谓语总是用复数，不能用单数，这类名词比较常见的有police(警察)，people(人)，cattle(牛，牲口)，clothes(衣服)等。如：

His clothes were in rags. 他衣衫褴褛。

The police are going into the murder case. 警察正在调查这件谋杀案。

Many cattle are suffering from a disease called BSE. 许多牛得了疯牛病。

2. 必须用单数的情形

有的集合名词作主语时，其谓语总是用单数，不能用复数，这类名词比较常见的有clothing(衣服), poetry(诗歌), baggage / luggage(行李), furniture(家具), scenery(景色), jewellery(珠宝), equipment(设备)等。如：

Furniture is chiefly made of wood. 家具主要是由木材制造。

Poetry serves to stimulate the mind. 诗歌能激发心灵。

My baggage has been sent to Greece by mistake. 我的行李被误运到希腊去了。

In fact, cattle are one cause that leads to the problem.

3. 主谓一致——根据意义确定单复数情形

有的集合名词用作主语时，其谓语既可用单数，也可用复数：当它们被视为整体时，谓语用单数；当它们强调个体时，谓语用复数。这类名词比较常见的有family(家庭)，team(队员)，class(班上的全体学生)，crowd(人群)，government(政府)，crew(乘务员)，committee(委员会)，audience(听众)，public(公众)等。如：

My family is very large. 我家人很多。(视为整体)

His family are waiting for him. 他家里人在等他。(强调个体成员)

注：有时没有特定的上下文，用单数或复数谓语区别不大。如：

Our discussion group is [are] meeting this week. 我们的讨论小组本周开会。

The public are [is] requested not to leave litter in the park.要求公众在公园不要乱扔东西。