Concrete is a mix of cement, gravel, sand and water.

混凝土是水泥、砾石、沙子和水的混合物。

GAZA run by the Hamas Islamist movement has struggled with an acute shortage of cements, gravel and steel, because Israel feared they would be used to fortify defenses.

被哈马斯武装运动控制的加沙地带苦于应对水泥、石子和钢铁短缺问题，因为以色列担心这些材料可能被用来加固防御工程。