誤了大事 A Great Business Spoiled
八戒道：「師父教我來迎你，因認不得山路，商議良久，教土地引我，故此來遲，如何誤了大事？」行者道：「不是怪你來遲，這潑牛十分無禮。八戒道：「师父教我来迎你，因认不得山路，商议良久，教土地引我，故此来迟，如何误了大事？」行者道：「不是怪你来迟，这泼牛十分无礼。
逐句解 Line by line
Eight Rules said: "The master sent me to meet you, and because I did not know the mountain road we talked it over a long while and had the local god guide me. That is why I am late. How have I spoiled any great business?"
The defence is point by point and entirely sound, and every clause of it can be checked against the previous passage. 認不得 takes the light linking de: the character sits under a "can/cannot" frame with 不, hooking one verb to another, the same shape as 去不得. The tone settles without help, since 不 is bù before a rising tone and before an unstressed syllable alike. Both 教 are jiào, "had someone do".
Pilgrim said: "It is not that I blame you for being late. This wretched bull is beyond all decency.
The concession is quick and complete, and it matters: the Great Sage withdraws the charge in the same breath he made it, which he does not often do. 十分 takes 分 at fēn, "ten parts, wholly". (不 rises to bú before the falling tone of 是.)
Eight Rules defends himself point by point and the defence is entirely sound: he was sent, he did not know the road, the delay was spent taking advice, and the advice produced a guide. Every clause can be checked against the previous passage, and the reader has watched all of it.
如何誤了大事 turns the accusation back as a question, which is the shrewdest move available to him, and it works at once. 不是怪你來遲 concedes the whole point in five characters.
What the concession opens is the passage that follows, in which the Great Sage has to say out loud, to the brother he has just wrongly blamed, exactly how the fan was lost. The structure is careful: the false accusation exists so that the true account has to be given.