But, at the preconcerted signal, the two men climbed through the window and disappeared from view.

但是，在预先设定的信号下，这两个人爬出窗户，消失在视野中。

As soon, therefore, as David gave the preconcerted signal, a low hissing sound was heard in the lodge in place of the fierce growlings of the bear.

因此，就在大卫发出预先设定的信号时，小屋里响起一阵低沉的嘶嘶声，代替了熊的凶猛咆哮。