These metals may be purified by a technique called zone refining .

这些金属可以用所谓“逐区提纯法”来提纯。

youdao

These metals may be purified by a technique called zone refining.

这些金属可以用所谓“逐区提纯法”来提纯。

youdao

These metals may be purified by a technique called zone refining.

这些金属可以用所谓“逐区提纯法”来提纯。

youdao