北京烤鸭烤好时，香味让所有外国食客都垂涎三尺了。(by the time)

By the time the Peking duck was roasted / done / ready, the smell had made all the foreign diners’ mouths water.

考查从句和时态。本句是时间状语从句，使用了 “by the time” 结构，表示 “到了……时候”。从句为一般过去时，主句为过去完成时。“北京烤鸭烤好时” 翻译成一般过去时被动语态。“北京烤鸭” 为the Peking duck，为主语。“烤好” 为翻译为：was roasted / done / ready。“香味” 为the smell，“所有外国食客” 为all the foreign diners。make one’s mouth water是固定搭配，表示 “让某人垂涎欲滴”。故翻译为：“By the time the Peking duck was roasted / done / ready, the smell had made all the foreign diners’ mouths water.”。