我輩不能 “We Cannot”
那道士怎麼有那樣本事？就叫，那龍王見大聖在此，也不敢出頭。道士云：「我輩不能，你是叫來。」那道士怎么有那样本事？就叫，那龙王见大圣在此，也不敢出头。道士云：「我辈不能，你是叫来。」
逐句解 Line by line
How could those Daoists have any such power?
那道士 and 那樣: 那 = nà. 本事 "ability, real skill" -- and the narrator asks the question rather than a character, which is the novel dropping the pretence of suspense.
Even if they called, those Dragon Kings, seeing the Great Sage here, would not dare put out their heads.
那龍王: 那 = nà. 不敢出頭: the third tone of 敢 keeps 不 at bù -- "would not dare put their heads out." Even if the Daoists called correctly, the dragons would stay hidden, because the Great Sage is standing there.
The Daoist said, “We cannot do it — you call them.”
我輩不能: the rising tone of 能 keeps 不 at bù. 你是叫來 "you are the one to call them" -- four words of surrender, and the first honest thing any of the three has said.
The narrator answers the question before the immortals do: of course they cannot, and even if they could, the dragons would keep their heads down with the Great Sage watching.
"We cannot do it -- you call them." It is a complete capitulation, and it is worth noticing that they do not attempt a bluff. There is no point. This is the one claim in the whole dispute that gets tested the moment it is made.