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: The email, as it was open and apparently unfinished, could have easily been a clue as to the whereabouts of General White and his family.

SOLUTION: Singular

PROBLEM: Only insects and vermin will grow in your fields !

SOLUTION:
Plural