"To His Coy Mistress" (1681), by Metaphysical poet Andrew Marvell (1621-1678), is almost guaranteed to appear on the GRE Literature exam.
The poem, an injunction to the speaker's mistress to forfeit her virginity in light of the couple's mortality, is often interpreted as a parody of the Cavalier style, marked as such by its metaphysical themes.
The poem is written in iambic tetrameter couplets.
Know the following by memory:
"But at my back I always hear
Time's winged chariot hurrying near;
And yonder all before us lie
Deserts of vast eternity."