"In chapter 7, Heathcliff expresses that he wishes to “be good” and asks Nelly for help. She attempts to give Heathcliff a makeover, she tells him to change his expression:
'Do you mark those two lines between your eyes, and those thick brows, that instead of rising arched, sink in the middle, and that couple of black fiends...'" Andrew Porter
Andrew here chooses a quote that not only supports his argument on the importance and fluidity of character expressions in Wuthering Heights, but one that's also fat with detail, wordage, and meanings that he will be able to draw on later when he picks the quote apart.