例句與造句

1. The Cygnus Loop has been observed several times during the flight.
2. Because of its appearance, it is also called the Cygnus Loop.
3. Astronauts pointed the shuttle instruments toward a supernova known as the Cygnus Loop so scientists can figure out how shock waves from the long-ago explosion are affecting clouds of interstellar dust.
4. It's difficult to find cygnus loop in a sentence. 用cygnus loop造句挺難的