Plurals with no singular forms

Some words, such as police (polizia), cattle (bestiame), staff, crew (equipaggio),  may seem “singular” but are in fact “plural”.

These words are used to talk collectively about things, people or animals.

Here are some examples:

Many cattle are suffering from a disease called BSE. (NOT Much cattle is…)

Cattle is a plural word used to talk collectively about bulls, cows and calves. It has no singular, and cannot be used for counting individual animals (one cannot say, for instance, three cattle).

Police, staff and crew are generally used in the same way.

The police are on strike. (NOT The police is…)

The staff are on strike. (BUT A member of staff said …, NOT a staff…)



Scrivener M, Practical English Usage (OUP 2005: page 517)