mixture

Concrete is a mixture of cement, sand, and gravel that becomes rock-hard when dry.

(Chinese) 混凝土是水泥、沙子和碎石的混合物，干燥后会变得像岩石一样坚硬。

The atmosphere is a mixture of nitrogen, oxygen, and small amounts of other gases.

(Chinese) 大气是氮气、氧气和少量其他气体的混合物。