Impermeable formations, such as shales and siltstones, tend to be finer grained or of a mixed grain size, with smaller, fewer, or less interconnected pores.

不渗透的地层如页岩与粉砂岩。因颗粒很细或粗细颗粒混杂。只有较小，较少连通不好的孔隙。

youdao

The alternative approach is simpler but does not provide as fine-grained control. Since the two approaches manage line buffering differently, they should not be mixed.

虽然这种替代方法更简单，但并不具备细节控制能力。因为这两种方法处理行缓存的方式不同，千万不能搞混。

youdao

When he shone a light up through it, he could see fine-grained particles of silica, known as chert, mixed in with what looked like coal.

NEWYORKER: The Martian Chroniclers