唯物论的英文：
materialism

Idealism is opposite to materialism.
唯心论和唯物论是对立的。

"Whether it is Hegel's idealism or Engels' materialism, they all converge at a common point."
无论黑格尔的唯心论或者恩格思的唯物论都强调了一个共同点.

The same applies to ideology, idealism will be replaced by materialism and theism by atheism
意识形态也是一样，要用唯物论代替唯心论，用无神论代替有神论。

invest material
覆盖材料

opaque materials
不透明物

This material is recyclable and will not pollute the environment.
这种材料是可循环利用的，因而不会污染环境。

It's a material of substance.
那是一种坚固的材料。

An ordinary mediocre material
中等人材