Interested in Language
The four in the title are always used as Collective Nouns, which means they have no singular form. That also means if we want to describe an individual of them, we can't directly put "a" or "an" before these words. Here are my opinions:
1. Cattle only can be modified with something like "a head of", "two head of", "a herd of" and "two hears of".
2. How can I deal with "police"? Can I say "two police" or "two of the plice"? Which is/are correct?
3. "A suit of" an "Two suits of" can be put before clothes.
Could you please help me with them? Thank you so much.
You can put 'some' or 'a few' before all of those. 'A couple of' can used with police and people.
police - "two police officers"
clothes - a pile, heap, closet-full, suitcase-full ...
Actually, with people, you can say "The Vikings were a war-like people." But this is a fairly uncommon usage, and you won't need to use it.