USAU

例句：

1. 1. The USAU is a new type of aircraft that can fly at high altitudes.
   USAU是一种新型飞机，可以在高海拔飞行。
2. 2. The USAU has been developed to improve the efficiency of air traffic control.
   USAU已经被开发出来，以提高空中交通管制的效率。
3. 3. The USAU is expected to be launched into space by 2025.
   预计USAU将于2025年发射进入太空。