The airport control tower kept postponing the ______ of our plan

The airport control tower kept postponing the ______ of our plane,which annoyed us greatly. (depart)
【正确答案】：departure
【题目解析】：译文：机场的指挥塔台一直在延迟我们的航班的起飞，令我们十分生气。此处post-pone后面需要名词形式，表示的耽搁，延退。答案为departure。