答案：C

题目分析：考查时态，由后面的时间状语in a few days，时态是将来时，短暂性动词进行时，表示将要做某事，句中有when，引导的时间状语从句，主语是the earliest plane，take off意思“起飞”，所以选C

点评：时态是高考常考内容，尤其是短暂性动词的进行时表示将要做某事，是常考内容，要求考生掌握其用法

即学即练：---John, why are you so upset?

---I­­­      my cell phone all morning but it is nowhere to be found.

A. am looking for                         B. have looked for

C. have been looking for                      D. had looked for

选C