Question

求英语高手帮忙翻译个英语句子，鄙人不才半天弄不懂，谢谢！

you will hace to come back a day before the flight leaves to check for cancellations

Answer 1

you will have to come back a day before the flight leaves to check for cancellations.
1、如果你要取消行程（退机票），你必须在航班离港前一天回来（办理退票手续）。
还可以理解成：
2、你必须得在航班起飞前一天回来查明航班是否被取消。