公公高姓 Your Honoured Surname
不多時，漸漸黃昏，老者又叫掌燈。行者躬身問道：「公公高姓？」老者道：「姓李。」行者道：「貴地想就是李家莊了？」老者道：「不是，這裡喚做駝羅莊，共有五百多人家居住。別姓俱多，惟我姓李。」行者道：「李施主，府上有何善意，賜我等盛齋？」不多时，渐渐黄昏，老者又叫掌灯。行者躬身问道：「公公高姓？」老者道：「姓李。」行者道：「贵地想就是李家庄了？」老者道：「不是，这里唤做驼罗庄，共有五百多人家居住。别姓俱多，惟我姓李。」行者道：「李施主，府上有何善意，赐我等盛斋？」
逐句解 Line by line
Before long the dusk came gradually on, and the old man called again for the lamps to be lit.
掌燈 is to tend or hold up a lamp. The doubled 漸漸 slows the sentence down to the speed of the light going.
Pilgrim bowed and asked, "What is your honoured surname, grandfather?"
公公 belongs to a whole class of Chinese address terms built by doubling a syllable — grandfather, elder brother, and so on — and every one of them lets the second syllable go unstressed. 高姓, "your lofty surname," is the standard courtesy for asking a name.
The old man said, "Li."
Two characters of speech, and the line still stands alone: it names its speaker and closes its own quotation, which is what keeps even the shortest replies from being folded into their neighbours.
Pilgrim said, "Then this honoured place will be Li Family Village, I take it?"
想 here is "I take it" rather than "to think of" — a hedge on a guess. Pilgrim is making conversation, and he is wrong.
The old man said, "It is not. This place is called Tuoluo Village, and there are five hundred households and more living in it.
The village finally gets its name, and the first two characters of it are the ones standing in the chapter's title. It has been withheld for more than eleven hundred characters, though the party reached the gate long ago.
"Other surnames are plentiful here. I am the only Li."
Eight characters — which is exactly the cut-off for tucking a quotation-closing tail into the segment before it. The rule takes tails of fewer than eight, so this one stands on its own.
Pilgrim said, "Patron Li, what kindness of your household moves you to grant us so lavish a meal?"
盛 is shèng, abundant. 善意, "kind intention," is the word he leans on: Pilgrim is after the motive, not the food.
The scene opens on lamps being lit and small talk, and turns into an interrogation. Pilgrim asks for the surname, guesses the village name from it, gets corrected, and then puts the question he has been working towards since the plates were cleared.
The correction is the substantive part. Five hundred households and only one Li: the old man is not the village patriarch but an ordinary householder, which makes the lavishness of the meal harder to explain rather than easier.
府上有何善意 is a polite sentence with nothing polite underneath it. Pilgrim told Eight Rules he had a way of handling this, and here it is — ask outright what the food was for.