感謝不盡 You Did Not Fight Them
長老感謝不盡道：「你這番不曾與妖精賭鬥麼？」行者道：「不曾。」長老道：「這等保不得我過山了？」行者是個好勝的人，叫喊道：「我怎麼保你過山不得？」长老感谢不尽道：「你这番不曾与妖精赌斗么？」行者道：「不曾。」长老道：「这等保不得我过山了？」行者是个好胜的人，叫喊道：「我怎么保你过山不得？」
逐句解 Line by line
The elder, thanking him beyond ceasing, said, "So this time you did not have it out with the demons?"
不盡 forces the tone of 不 upward to bú. The reason is worth knowing: 盡 is fixed to a falling tone across this project, and 不 always shifts to the rising tone before a falling one. The earlier chapters carry this exact compound nine times and read it bú at eight of them.
Wukong said, "I did not."
Two characters, and they are about to cost him the rest of the chapter.
The elder said, "Then you can't get me over the mountain?"
保不得 puts 得 in the light de, the cannot-manage-to grammar. And this is Xuanzang being unexpectedly sharp: he has gone straight from gratitude to the practical question in one sentence.
Wukong was a creature who had to win, and he shouted out, "How do you mean I can't get you over the mountain?"
The narrator names the flaw outright — 好勝, fond of winning — which the book almost never does. He then repeats the master's own words back with the negation moved to the end, which is what people do when they have been stung.
The trap here is conversational rather than magical and Wukong walks into it faster than he walked into the bottle. He has just escaped a treasure of yin and yang by drilling a hole in it, and two sentences of mild scepticism from his master have him shouting.
It is worth noticing that Xuanzang is not being unreasonable. Nothing about the cave has changed: the doors are shut, the three chiefs are alive, and the road still runs through it. The disciple has had an adventure and the master has a logistics problem, and they are the same fact seen from two positions.