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: A clump of cobwebs sprouted from the rotten scalp, drifting slowly in the frozen wind.

SOLUTION: Singular

PROBLEM: Sentinels guarding the armory are unresponsive. "

SOLUTION: Plural

PROBLEM: The simplicity of the kiss both stunned and aroused her.

SOLUTION:
Singular