原文 Original text
繁體 Traditional
Reader's edition
計上心來 A Plan Comes To Her
那孫大聖精神抖擻，棍兒沒半點差池。妖精自料敵他不住，猛可的眉頭一蹙，計上心來，抽身便走。那孙大圣精神抖擞，棍儿没半点差池。妖精自料敌他不住，猛可的眉头一蹙，计上心来，抽身便走。
逐句解 Line by line
那孫大聖精神抖擻，棍兒沒半點差池。
那孙大圣精神抖擞，棍儿没半点差池。
That Great Sage Sun had his spirits well roused, and there was not half a hair's error in his cudgel.
那 is nà, pointing at the fighter just described, and 兒 is ér. 差池 is a slip or a discrepancy — not one in the whole exchange.
妖精自料敵他不住，猛可的眉頭一蹙，計上心來，抽身便走。
妖精自料敌他不住，猛可的眉头一蹙，计上心来，抽身便走。
The fiend reckoned for herself that she could not hold out against him, knitted her brows all at once, and a plan came into her heart, and she pulled away and ran.
計上心來, a plan comes up into the heart, is the standing phrase for a sudden stratagem. 猛可的 is vernacular for abruptly.
The stalemate breaks, and it breaks on thinking rather than on strength. She works out that she cannot win the exchange and immediately stops trying to.
The novel is careful to say that Pilgrim was flawless. He did not make the mistake. He simply had no answer to an opponent who declined to keep fighting.
Knitting the brows and then having a plan arrive is one of this book's stock gestures, and it is nearly always the signal that its owner is about to do something the hero has not anticipated.