为什么在我的金属箍的中间部分没有黑镍这个问题，就得用上好多页纸才能回答清楚。

The complete story of why the center of my ferrule has no black nickel on it would take pages to explain.

youdao

用于纸和纸版生产中的结构构成剂。精选铜镍和钾矿石时的浮选剂。

For the structure of paper and paper production in the form of agent. Flotation agent selected nickel copper and potassium ore.

youdao

用于纸和纸版生产中的结构构成剂。精选铜镍和钾矿石时的浮选剂。

For the structure of paper and paper production in the form of agent. Flotation agent selected nickel copper and potassium ore.

youdao