大吃一惊

Explanation: Describe what happened to the surprise 　　Usage: Partial official; as predicate; describe very surprised 　　Source: Ming Feng Meng "Jingshitongyan" Volume 28: "It is an outside member of surprise, turned around and went away, came back, looking down upon the." 　　Examples: The friend and he met again, can not help ~. ★ Ba Jin, "waiting for looking forward," Thesaurus:  Surprised extremely, vitally startle