spring sth. on someone  =to do sth, ask sth or say sth that sb is not expecting 突如其来地做；冷不防地问；突然说

　　She sprang a surprise by winning the tournament. 这次比赛她获得冠军，爆了个大冷门。 

　　I'm sorry to spring it on you , but I've been offered another job. 我很抱歉这样突然告诉您，我另有工作了。

　　So, she apologized for springing her happy news on me out of the blue like that.也因为这个原因，她为自己的好消息对我之突然而道歉。

　　He asked, "A week? How can you spring this news on me?

　　他问，"一周？你怎么可以这么突然"？

　　spring[ V+ adv./prep.] to appear or come somewhere suddenly 突然出现（或来到）

　　Tears sprang to her eyes. 她眼里一下子涌出了泪水。

　　Where on earth did you spring from? 你究竟是从哪儿冒出来的？ 

　　spring up like mushrooms 像雨后春笋一样拔地而起

　　After videos about making cupcakes became popular online, stores specializing in cupcakes "sprang up like mushrooms" all over town.

　　制作纸杯蛋糕的视频在网上走红后，专门制作纸杯蛋糕的商店"如雨后春笋般涌现"，遍布全城。

　　New houses have sprung up like mushrooms. 新房就像雨后春笋一样拔地而起。

　　As a result, short-term English training courses are springing up like mushroomseverywhere across the country. 因此，一些短期英语培训班如雨后春笋般在全国各地出现了。