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: Clearly, a notion she hadn't suspected.

SOLUTION: Singular

PROBLEM: The female dwarves had agreed to go as far as the camp to make the numbers look fiercer than they actual were.

SOLUTION: Plural

PROBLEM: His kisses were rough and desperate, his tongue matching the pace of his thrusts.

SOLUTION:
Plural