---I drove to Zhuhai for the air show last week.---Is that the reason ______ you had a few days off?

---I drove to Zhuhai for the air show last week.

---Is that the reason ______ you had a few days off?

A.why

B.when

C.what

D.because

答案及解析： A

解析：

reason作先行词，定语从句用why引导。