Sonnet 130 - Shakespeare - Can you please explain what my teacher means by this?

In the form, as you see from the other sonnets surrounding this one, Shakespeare uses the last couplet to run a counter theme or contrast to the preceding three quatrains, abab,cdcd, efef, gg. The comparisons given are false, as is the supposition that his mistress might be a goddess, one who walks some supposed heaven. He sees beauty without resorting to flowery descriptions or hyperbole.