drop a,the,his,etc.bombshell:犹如掷了一颗炸弹,突如其来地宣布使人震惊且通常令人不快的事
She dropped a bombshell at the meeting and announced that she was leaving.
她在会上宣布了令人吃惊的消息,说她将要离开.
It was then that he dropped the bombshell--he wasn't planning to come with us.
那时他突然宣布一个令人不快的消息,他不准备跟我们一起去了.
a drop in the bucket/ocean:an amount of something that is too small or unimportant to make any real difference to a situation 沧海一粟;九牛一毛
$10 million is only a drop in the bucket compared to what is needed to help these people effectively.
要有效地帮助这些人,1000万美元只是九牛一毛而已.