我看到一只燕子在屋檐下筑巢。

I saw a ___tsubame building its nest under the roof.

在日本，人们常在新年时悬挂燕子的装饰品以求好运。

In Japan, people often hang ___tsubame decorations during New Year for good luck.

那个短跑运动员因为速度惊人，被人们亲切地称为“飞燕”。

The sprinter was affectionately called ___tsubame for his astonishing speed.