我们爬了三段楼梯才到达顶楼。

We climbed three ___flights of stairs to reach the top floor.

我们预订了明天早上飞往巴黎的航班。

We've booked morning ___flights to Paris for tomorrow.

一群野鸭从湖面上飞过。

A ___flight of wild ducks flew over the lake.