Greg: She's the most far-out chick in my class. You wouldn't believe how much I dig her. Alice: Sure, I would. I've been digging Sam so long, by the time he proposes, I'll be six feet under.
Greg remarks about how no one could believe how much he digs Donna. Alice retorts that yes she can, as she has been digging Sam so long by the time he asks for her hand she will be buried.