angular gravel造句

Sedimentary rocks that contain a mixture of rounded and angular gravel clasts are sometimes called breccio-conglomerate.
Either moist subsoil that contains enough clay to become cohesive when tamped, or an angular gravel or crushed volcanic rock is used . ( Sandbag structures with sand fills are an alternative technology and require very different construction details ).
It's difficult to find angular gravel in a sentence. 用angular gravel造句挺难的