Literal:
* The knell of the church bell echoed through the valley, signaling the end of the funeral service.
* The knell of the ship's bell marked the passing of another hour at sea.
Figurative:
* The news of his sudden death was like a knell to our hopes for the future.
* The constant barrage of bad news served as a knell to the nation's optimism.
* The company's stock price plummeted, sounding the knell for its demise.
Remember: "Knell" often has a somber or mournful tone, associated with death, loss, or the end of something.