低著頭走 Walk With Your Head Down
三藏只叫：「不要撞禍，低著頭走。」八戒遵依，把個蓮蓬嘴揣在懷裡；沙僧不敢仰視；惟行者東張西望，緊隨唐僧左右。三藏只叫：「不要撞祸，低着头走。」八戒遵依，把个莲蓬嘴揣在怀里；沙僧不敢仰视；惟行者东张西望，紧随唐僧左右。
逐句解 Line by line
Tripitaka could only call out, "Do not go courting trouble. Keep your heads down and walk."
著 is the weak zhe that marks an action held in progress — heads kept down while walking. The machine offers zhù, which belongs to writing and authorship and has nothing to do with either sense this chapter uses.
Eight Rules did as he was told, and tucked that lotus-pod snout of his away inside his shirt;
揣 is chuāi, to stow something inside one's clothes, not chuǎi, to size a thing up. 蓮蓬嘴 — a snout like a lotus seed-head, all holes and knobs — is the standing epithet for the pig's face.
Sha Monk did not dare to raise his eyes;
Six characters against thirteen on either side: the shortest of the three responses and the only one with no second clause. The source ends it with a semicolon like its neighbours, and that is why it is kept separate from them.
only Pilgrim looked this way and that, keeping close at the Tang Monk's side.
The source cuts this sentence into three at its semicolons, and the three stay apart. The first two do not match in depth — one carries a clause of obedience before its action, the other a bare negative — and this third opens with 惟, which turns against what came before rather than continuing it.
Three disciples, three responses, and the grammar sorts them out. Eight Rules obeys by hiding the offending part of himself, Sha Monk obeys by not looking up, and Pilgrim does not obey at all — he looks everywhere, and stays close.
The instruction itself is worth noticing. Tripitaka does not tell them to behave; he tells them not to be seen. His anxiety in this kingdom is always about attracting notice, and it will turn out to be well founded for reasons he has not begun to guess.