不要严酷
发表于 2025-3-30 08:29:16
Book 1994e ancient Chinese people have made outstanding contribu tions. In the book ‘Lu‘s Spring and Autumn‘, written near the end of the Warring States Period, i. e. in the third century B. C. , there is a statement on the "attraction of iron by lodestones". So at that time it was known that magnets can at