a steep gradient的用法和样例：
- They farm their land, coaxing vines, lemons, olives and basil out of a plot that defies gravity.It towers over the sea on such a steep gradient, I wonder how anything grows.
- There was a steep climb on the road out of town.
- The climber had to negotiate a steep rock face.
- The mountain rise up in a steep wall of rock.
- The mountain rose up in a steep wall of rock.
- Our car stalled on the brow of a steep hill.