a lifeless planet的用法和样例：
- Such stability was a clear gravestone marking a lifeless planet.
- In the oceans, the evolution of organisms with shells and mineralized skeletons generated thick layered deposits of minerals such as calcite, which would be rare on a lifeless planet.
- The Negeb was a barren, terrible desert, a lifeless desert.
- Earth's first nearly full look at Mercury reveals that the tiny lifeless planet took a far greater role in shaping itself than was thought, with volcanoes spewing "mysterious dark blue material.