a sharp ridge的用法和样例：
- A sharp ridge with steeply sloping sides, produced by erosion of the broken edges of highly tilted strata.
- Starting from Camp 1, they trekked through a sharp ridge through an 800-meter wall that was believed to lead to the peak.The ridge, however, dropped to a cliff.
- You need a sharp knife to cut through the knot.
- I cut my finger on a sharp stone.
- A sharp knife makes a clean cut.