嘴長耳大 After Him After Him
他只道嘴長耳大，手硬鈀兇，敗了陣，丟了刀，回頭就走。大聖喝道：「趕上，趕上。」這獃子仗著威風，舉著釘鈀，即忙趕下怪去。他只道嘴长耳大，手硬钯凶，败了阵，丢了刀，回头就走。大圣喝道：「赶上，赶上。」这呆子仗着威风，举着钉钯，即忙赶下怪去。
逐句解 Line by line
He took it for a long snout and big ears, a hard hand and a savage rake — lost the field, dropped his sabre, turned his head and ran.
長 is cháng, long — the measuring band, not the zhǎng of growing. The demon's assessment is entirely physical: snout, ears, hand, rake. He has not been beaten by skill and he knows it.
The Great Sage shouted, "After him! After him!"
喝 is hè, the shout. The doubled order is the fourth time somebody in this chapter has said a thing twice in a crisis — the cave's own habit, now caught by the other side.
The Idiot, riding on his own moment of glory and holding the rake up, chased straight down after the demon.
Both 著 take the light zhe — relying and going on relying, holding and going on holding. 仗著威風 is leaning on a display of power, which is precisely what Bajie is doing: he has frightened somebody once and is now living on it.
Wukong's instinct is to pursue and it is the wrong one. Everything about this demon's retreat is too quick — he was not losing a moment before — and the chapter has already shown us what happens when he stands still and opens his mouth.
Bajie chasing is the funnier half. He has landed exactly one blow in his life that worked, and he is now hurtling downhill after a creature four times his size on the strength of it. 仗著威風 is the narrator's dry assessment of what is carrying him.