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.
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Question: A mass of recruits had already gravitated to the Whites.

Answer: Singular


Question: " Dogs can be a nuisance. "

Answer: Plural


Question: Two recycling bins stood at the end of the alley.

Answer:
Plural