tǔ qǐ fú jǔ
凫：野鸭。象兔敢奔跑，象野鸭急飞。比喻行动迅速。
战国 吕不韦《吕氏春秋 论威》：“知其不可久处，则知所兔起凫举死殙之地矣。”
兔起凫举联合式；作状语；含褒义，用于书面语。
as fast as the hare runs and as swift as the wild duck starts flying
