不是发现过银和铅的混生矿吗？

Hadn't twined ores of silver and lead been found?

youdao

研究了雁门关农牧交错带不同一年生牧草及饲料作物混播草地的产草量。

The yield of the annual forage and feed crops mixture grassland in agro-pastoral transitional zone of Yanmenguan region in Shanxi was studied.

youdao

研究了雁门关农牧交错带不同一年生牧草及饲料作物混播草地的产草量。

Effect of the annual forage and feed crops mixture at different rate and sow methods in the Shanxi region of agro-pastoral transitional zone was studied.

youdao