钻铤必须是由非磁性物质做成的。

The drill collars must be made of nonmagnetic material.

youdao

非磁性物质不能制成磁铁。

A non-magnetic substance cannot be made into a magnet.

youdao

非磁性物质不能制成磁铁。

A non-magnetic substance cannot be made into a magnet.

youdao