Pride and Prejudice

Elizabeth was surprised, but agreed to it immediately. Miss Bingley succeeded no less in the real object of her civility; Mr. Darcy looked up. He was as much awake to the novelty of attention in that quarter as Elizabeth herself could be, and unconsciously closed his book. He was directly invited to join their party, but he declined it, observing that he could imagine but two motives for their choosing to walk up and down the room together, with either of which motives his joining them would interfere. What could he mean? She was dying to know what could be his meaning? and asked Elizabeth whether she could at all understand him?