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: Despair might be the tune he sang to himself about what he did, but a deep polished vanity lay beneath it.

SOLUTION: Singular

PROBLEM: My teacher shifted uncomfortably.

SOLUTION: Singular

PROBLEM: The witch's illusion faded when he thought about the feminine spirits, even if her black blood was still wet on his blade.

SOLUTION:
Singular