porous iron-lead-graphite bearing

例句：

1. 1. The material is porous enough toallow air to pass through.
   这种材料足够多孔，可以允许空气通过。
2. 2. Thesoil is porous, allowing roots topenetrate easily.
   土壤是多孔的，使根系容易穿透。
3. 3. The sponge is porous and can absorb a lot of water.
   海绵是多孔的，能吸收很多水。