Tu-20

例句：

1. 1. The Tu-20 is a popular fighter jet in China.
   图-20是中国一款受欢迎的战斗机。
2. 2.The Tu-20 has been upgraded to improve its performance.
   图-20已经升级，以提高其性能。
3. 3. The Tu-20 is used for military purposes and is considered one of the most advanced fighter jets in the world.
   图-20用于军事目的，被认为是世界上最先进的战斗机之一。