茯苓膏 The Cakes Of Poria
四老請唐僧先吃，三藏驚疑，不敢便吃。那四老一齊享用，三藏卻才吃了兩塊。各飲香湯收去。四老请唐僧先吃，三藏惊疑，不敢便吃。那四老一齐享用，三藏却才吃了两块。各饮香汤收去。
逐句解 Line by line
The four old men invited the Tang Monk to eat first. Tripitaka was startled and doubtful, and dared not eat at once.
His hesitation is the first sign in three passages that he remembers how he got here. 不 keeps bù before the rising tone of 敢.
Then the four old men set to together, and only after that did Tripitaka eat two pieces.
卻才 is the timing word "only then", the same construction used of recalling the tiger hairs at the start of the chapter and of Tripitaka collecting himself after the abduction.
Each drank his broth, and the things were taken away.
Six characters of narration standing alone. It is a narrator clause and stands on grammar rather than on length.
Tripitaka will not eat until his hosts have. It is the one moment of caution he shows all evening, and the text gives it four characters — startled and doubtful, dared not eat — before moving on. He is not a fool about food; he has simply stopped being afraid of the company.
The precaution is also useless, and the novel knows it. Watching your host eat first is a guard against poison, and nothing here is trying to poison him. What the evening wants from Tripitaka is not his life but his participation, and the two pieces he finally eats are the point at which he accepts the invitation properly.