名词砂岩，天然砥石
1. 沙岩：石细胞 grit cell | 沙岩 gritstone | 腹股沟 groin
2. 尖角粗砂岩：gritmilltube 磨碎机 | gritstone 尖角粗砂岩 | grittingmaterial 粗砂 砂砾
gritstone是什么意思
noun
1. a hard coarse-grained siliceous sandstone
Synonym: grit gritrock