This is determined by the characters of metal production procedure as well as selective mining method itself.

这种情况是由于金属生产和选别式地下开采的特点而引起的。

youdao

This is determined by the characters of metal production procedure as well as selective mining method itself.

这种情况是由于金属生产和选别式地下开采的特点而引起的。

youdao