英语两天半怎么说

In English, you can say "two and a half days" or "two days and a half." Both expressions are correct and can be used interchangeably.
For example, you could say:
"I will be away for two and a half days."
"The conference will last for two days and a half."
You can also use the word "half" to indicate that something is incomplete or not finished. For example:
"I only have half a day off work today."
"I've only finished half of the report."
I hope this helps! Let me know if you have any other questions.