Sha Monk clove open a path through the water, and the brothers went down together into the River That Reaches to Heaven.

剖開水路 — the parting of water is Sha Monk's proper craft, learned in his exile at the Flowing-Sand River. 通天河, the River That Reaches to Heaven, has been the setting since chapter 47.

They had gone a hundred li and more toward the riverbed when the blockhead thought to play his trick on Pilgrim.

里 is kept untransliterated as li; 百十里 is an idiomatic "a hundred or so." 那獃子 deictic 那 nà.

Pilgrim at once plucked out a strand of hair, changed it into a false body, and set it lying on Eight Rules's back;

背 here is the noun bèi, "the back" — contrast the verb bēi at the end of the previous passage. The hair-double is Wukong's standard counter-measure, deployed pre-emptively because he has already read Bajie's intention.

while his true body he changed into a hog-louse, which clung fast within the pig's ear.

豬虱子, a hog-louse: the transformation is chosen for the ear, which makes Wukong an invisible auditor for the whole of the following exchange.

Eight Rules was walking on when all at once he lurched, and purposely flung Pilgrim forward, so that down he went with a slap.

躘踵 (lóng zhǒng) is a vernacular binome for stumbling or reeling. 得故子 is a Ming colloquial adverbial meaning "on purpose, deliberately"; 得 is read dé as a lexical morpheme within the fixed phrase, and 子 is the toneless suffix.

But that false body was only a hair transformed: up it floated and away, without shadow or shape.

無影無形 — the give-away. A real body would have sunk; the hair-double drifts, which is what betrays the substitution to the reader before it betrays it to Bajie.

Sha Monk said: "Second brother, what do you call this?

二哥, "second elder brother" — Sha Monk's fixed form of address for Bajie, who ranks between Wukong and himself.

You cannot even walk properly. Had you only fallen in the mud yourself, well and good — but now you have lost Elder Brother, and none knows where he has fallen."

便也罷了: 便 + 也 + 罷了, "and that would be the end of it." 罷了 is the fixed compound and reads bà in all positions, per the ratified rule: 罷了 = bà, 也罷 = bà, and only the bare sentence-final hortative 罷 (= 吧) is ba. 不知跌在那裡: 那裡 interrogative nǎ, "where."

Eight Rules said: "That monkey cannot take a fall — one tumble and he has dissolved away.

不禁跌: 禁 read jīn, "to withstand, to bear," not jìn ("prohibit"). 跌化了 treats Wukong as something that melts on impact — Bajie's improvised and self-serving physics.

Brother, never mind whether he is alive or dead. You and I will go on and look for our master."

莫管他死活 — the callousness is comic rather than sinister, and is precisely what Wukong, listening from the ear, is waiting to hear.

Sha Monk said: "That will not do. We still need him to come.

還得他來: 得 the modal of necessity, děi; 還 hái, "still." Sha Monk's insistence is practical, not affectionate.

He may not know the ways of water, but he is shrewder than we are.

水性, the nature and behaviour of water — a swimmer's competence. 乖巧, quick-witted; the concession is exact about what Wukong is good for underwater.

If he does not come, I will not go with you."

與 in the sense of 跟, "together with" — a vernacular usage standard in the novel's dialogue.

Pilgrim, inside Eight Rules's ear, could hold in no longer, and shouted: "Wujing, old Sun is right here!"

忍不住, could not restrain himself. 老孫 is Wukong's habitual self-designation, and its sudden sounding from inside the ear is the pivot of the scene.

Sha Monk heard it and laughed: "Done for! This blockhead is a dead man — how did you dare play tricks on him?"

Utterance-initial 罷了 is the exclamation of dismay, "done for!" — the same compound 罷了 that appeared eleven segments above in its limiting sense, and read bà in both, since 罷了 keeps the full tone in every position; only the bare hortative final 罷 (= 吧) reduces to ba. 聽得: 得 dé.

Now you have brought it to this: we hear a voice and see no face. What is to be done?"

弄得: 得 the complement particle de, introducing the resulting state 聞聲不見面.

Eight Rules was so alarmed that he knelt down in the mud and knocked his head, saying: "Brother, I was in the wrong.

慌得: 得 again the complement particle de, "so alarmed that…" — the same construction as 弄得 in the preceding segment.

When we have rescued our master, I will make my apologies ashore.

陪禮 (also written 賠禮), to make formal apology. Bajie defers the ritual to dry land, where it can be performed properly — and, he may hope, forgotten.

Where are you speaking from?

那裡 interrogative once more — 那 nǎ. Bajie still cannot locate the voice.

You have frightened me to death.

諕 is read xià (= 嚇), "to frighten," invariant across the corpus; pypinyin's default háo is wrong here and is corrected at every occurrence.

Do show your true body and come out. I will carry you, and never affront you again."

現原身, to resume one's true form. 馱著 durative 著 zhe.

Pilgrim said: "You are carrying me still.

哩 is the vernacular sentence-final particle, read toneless li throughout the corpus. 還 hái, "still" — the joke turns on the adverb.

I'll not torment you. Walk on, walk on."

快走，快走 — the doubled imperative closes the episode briskly, Wukong declining to prolong an advantage he has already taken.

The blockhead, muttering on and on, kept up his apologies as he scrambled to his feet and went forward again with Sha Monk.

絮絮叨叨, a four-syllable reduplicative for garrulous muttering. 念誦著 durative 著 zhe; 那獃子 deictic 那 nà.