歡娛夜短 Pleasure Makes The Night Short
正是寂寞更長，歡娛夜短。早不覺東方發白。那八戒幾鍾酒吃得興抖抖的道：「天將明了，等老豬下水去索戰也。」二郎道：「元帥仔細，只要引他出來，我兄弟們好下手。」八戒笑道：「我曉得，我曉得。」正是寂寞更长，欢娱夜短。早不觉东方发白。那八戒几钟酒吃得兴抖抖的道：「天将明了，等老猪下水去索战也。」二郎道：「元帅仔细，只要引他出来，我兄弟们好下手。」八戒笑道：「我晓得，我晓得。」
逐句解 Line by line
It is a true saying: in loneliness the watches are long, and in merriment the night is short.
Both graphs of the first clause needed correcting. 更 is gēng, the night-watch, and the parallel with 夜 in the second clause settles it; 長 is cháng, long. pypinyin gives the still-more gèng and the grow-up zhǎng, and is wrong at both. 正是 introduces nothing here and simply marks a proverb.
Before they knew it the east was turning white.
覺 is jué, to be aware, not the jiào of sleep, and its value settles the graph before it: 不 stays bù before a rising syllable. A short narrator's clause of seven graphs, standing alone on grammar rather than measure — the fourth of its kind in the chapter.
Eight Rules, with several cups of wine in him and quivering in good humour, said, "The day is nearly light. Let old Hog go down into the water and challenge them."
吃得 takes 得 at de, the linking reading, with the state of high spirits as its complement. 興 is xìng, and 興抖抖 is a vernacular reduplication for being all of a quiver with eagerness. 了 is the particle le, where pypinyin gives the verb liǎo.
Erlang said, "Careful, Marshal. You have only to draw him out, and my brothers and I can set to work."
仔 stands at zǐ by the corpus-wide ruling, where pypinyin gives zǎi. 元帥 is Eight Rules' celestial rank, Marshal of the Heavenly Reeds, and Erlang uses it — the only person in the chapter who addresses him by his title rather than as the idiot.
Eight Rules laughed and said, "I know it, I know it."
Both 得 are dé, the full verb, and both specs are given by position: 曉得 belongs with 認得, 聽得 and 記得 in the family where something is attained by a faculty. The repetition is the same two-fold form Pilgrim used at 真個罕有，真個罕有.
The proverb that opens the block does the work of a night. Nobody is shown drinking or talking; the reader is given two clauses of a saying about how time passes, then a line about the sky going white, and the feast is over.
Eight Rules wakes up brave. The novel is careful to say why — several cups of wine, and a state it calls 興抖抖, all of a quiver — and then has him volunteer for exactly the errand he spent the whole of yesterday evening avoiding. Nothing has changed about the errand.
Erlang's instruction is the same one Pilgrim gave and the same one the plan has always been: draw him out, and we do the rest. What is different is the form of address. Erlang calls him 元帥, Marshal, which is his rank in heaven and which nobody else in this chapter uses.