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: Her fingernails bit into his scalp, lighting his nerve endings on fire.

SOLUTION: Plural

PROBLEM: Her spine straightened until the woolen blanket fell from her shoulders.

SOLUTION: Singular

PROBLEM: Her instinct was to launch at him with her fingernails, but she might actually do him physical damage.

SOLUTION:
Singular