譬如：
He died in a struggle with prison officers less than two months after coming to Britain.可否加in？
Instagram reached the 1 million users mark in just three month after its October 2010 launch.可否去掉in？
The trial began almost two months after the assassination. 可否加in？
But more than two months after the earthquake, many Haitians appear to still need urgent help finding food. 可否加in？
1. He died in a struggle with prison officers less than two months after coming to Britain.
2. Instagram reached the 1 million users mark in just three months after its October 2010 launch.
3. The trial began almost two months after the assassination.
4. But more than two months after the earthquake, many Haitians appear to still need urgent help finding food.
【答】1, 3, 4 句都不可以添加介词 in；第3句则不可以省略介词 in。
零介词 + 时间段 + after + 时间点、事件名词、从句：用于句中修饰谓语动词，说明谓语动词在“时间段过去之后” 那个点位开始发生。比如，第1句的 died two months after coming to Britain，是指 “在来到英国两个月后死亡”，切不可翻译为 “两个月内死亡”。其他两句也是一样。
第2句，跟其他三句不同，时间段加 in 后，指谓语动词在这个时间段内发生。不像其他三句，在时间段过去之后开始发生。in just three months 指 “在十月发布后的短短三个月内就有了100万用户”。
