TASK DEFINITION: In this task you are given a sentence. You must judge whether subject of the main clause is singular or plural. Label the instances as "Singular" or "Plural" based on your judgment.
PROBLEM: " The usual suspects manned the barricades, and they pelted us with stones and bricks.

SOLUTION: Plural

PROBLEM: My contract is one of the best. "

SOLUTION: Singular

PROBLEM: The marble was at least a foot thick, with silver flecks sparkling like diamond chips in the smooth, glossy surface.

SOLUTION:
Singular