a prolonged illness的用法和样例：
- Frail and enfeebled, as from prolonged illness; emaciated.
- After a prolonged battle, they managed to drive out the invaders.
- After a prolonged siege, the town was rendered up to the insurgents.
- are designed to help offset heavy medical expenses that can result from a prolonged illness or serious injury.
- Every father should insure himself against premature death or prolonged illness for the sake of his wife and children.