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.

Behind Augustine, an elegant silver Porsche sat in a parking spot, all alone.
Singular

With a flounce of her skirts, the maid disappeared.
Singular

Mathematical equations, no matter how convoluted, cannot avoid following each minute step in the evolution of the scene.

Plural

