Collective Noun

[FrankOse]

A flock of sheeps is/were running around the field.

which verb is correct?

What determines the verb?
Is it "A flock" ?
Or is it "Sheeps"?

It has always confused me.
I hope someone can teach me the basic rule of collective noun.

Thanks in advanced.

[David L.]

plural of 'sheep' is 'sheep', not 'sheepS'

The verb agrees with the subject of the sentence. In the sentence:

'A flock of sheep is running around the field.'

'flock' is the subject.

[FrankOse]

plural of 'sheep' is 'sheep', not 'sheepS'

The verb agrees with the subject of the sentence. In the sentence:

'A flock of sheeps is running around the field.'

'flock' is the subject.

Thank you Sir for your correction and teaching!