原文 Original text
繁體 Traditional
Reader's edition
言之極當 Most Aptly Said Elder Brother
沙和尚滴淚道：「大哥言之極當。你兩個著意，我在此處看守。」沙和尚滴泪道：「大哥言之极当。你两个着意，我在此处看守。」
逐句解 Line by line
沙和尚滴淚道：「大哥言之極當。
沙和尚滴泪道：「大哥言之极当。
Sha Monk said through his tears, "Eldest brother, that is most aptly said.
極當 is entirely fitting, and 當 is dàng for that sense — apt, on the mark — rather than the far commoner reading of the same character. Sha Monk gets twelve characters here and they are all agreement.
你兩個著意，我在此處看守。」
你两个着意，我在此处看守。」
You two put your minds to it, and I will keep watch in this place."
著意 is to apply the mind, take care, and 著 is zhuó in it — the apply reading, one of only three places in the chapter it is right. The whole of Sha Monk's part in this chapter is contained in these two lines: agree, and stay behind.
Sha Monk is the least visible of the three and the novel keeps him that way. He speaks twice in this whole stretch, and both times to confirm somebody else's plan.
It is worth noticing that he does not ask why he is the one left behind, or point out that the arrangement condemns him to sit by a grave. The book gives him no resentment at all, which over a hundred chapters becomes a kind of character in itself.