impervious rock是什么意思 impervious rock怎么读
impervious rock的用法和样例
- There are also vast numbers of shells in the sedimentary rock and littering the cave floor, some of which may be part or middles-the garbage refuse of prehistoric cave dwellers.
在水岩石中还有很多贝类和树叶等残留物在洞穴的地面，那些部分是中世纪时居民入住洞穴的残留物。
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