In basic terms concrete is made up of stones, sand, cement and water.

在基本术语中，混凝土由石头、沙子、水泥和水组成。

Nearly four months later after several failed attempts, the Southern California Gas Company says it has permanently sealed the well by pumping in heavy fluid sand cement.

经过多次失败尝试，历时近四个月后，南加州天然气公司日前表示，通过大量灌注混凝土流砂，泄漏得以永久封堵。