问多久以后用英文怎么说

用英语表达"多久以后"可以用以下几种方式：

"In how long"
"After how much time"
"How much later"

例句：

In how long will the meeting start?
(会议什么时候开始？)
After how much time will we arrive at the airport?
(我们多久后到达机场？)
How much later will the train arrive?
(火车多久以后到达？)

这些表达方式来自英语的日常使用。