a long chance的用法和样例：
- It's a long chance to build a city in the desert.
- You took a long chance when you decided to go travelling with that strange man.
- There was a long lag in forwarding mail to us.
- Fruit juices ferment if they are kept a long time.
- The beggar spun a long yarn about his misfortunes.
- It was a long trudge up the hill.