“出人意料或重磅消息”用英语表达是 drop a bombshell，还可以译为“令人震惊或引起轰动的消息”等，它的字面意思是“投炸弹”，寓意：

1、make an unexpected, startling or disturbing announcement
发出一个意想不到的、令人吃惊的或令人不安的通告

2、reveal surprising information or news
透露令人惊讶的信息或消息

它还有一种表达方式 drop a bomb，意思跟 drop a bombshell 一样。

例如：

1、My sister dropped a bombshell by announcing she was discontinuing her study for a job.
我姐姐宣布为了工作而停止学习，这是一个令人震惊的消息。

解析：by 和 through 都可以作为介词，有相近的意思，它们的主要区别是 by 用来提及某事的方式方法，而 through 是用于任何过程的介词。

2、Susam dropped a bombshell when she told us she is pregnant.
苏珊姆告诉我们她怀孕了，真是出人意料。

解析：when 引导的时间状语从句，从句中的谓语可以是持续性动词，也可以是非持续性动词。

3、I do not have the courage to drop that kind of bombshell on my family.
我没有勇气告诉我家人那个令人震惊的消息。

4、The boss dropped a bombshell, saying my leave application was rejected by the director.
当老板说我的请假申请被主管拒绝了的时候，真是出乎我的意料。

解析：现在分词短句 saying my leave application was rejected by the directorng 在句中作状语表伴随。

5、The Australian Cricket Board dropped a bombshell when they announced that they won't go to play the series in Pakistan this year.
澳大利亚板球理事会宣布今年不去巴基斯坦参加系列赛，这是一个重磅消息。

6、Jane dropped a bombshell when she said she was leaving.
简说她要走了，真是出人意料。