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: Things I caused with a pull of my bowstring.

SOLUTION: Plural

PROBLEM: Names, characters, businesses, places, events and incidents are either the products of the author's imagination or used in a fictitious manner.

SOLUTION: Plural

PROBLEM: And there, hidden in the dark shade of two gigantic cedar trees, was the fern grotto.

SOLUTION:
Singular