According to ancient records, natural magnets were employed in China as direction-finding devices. This led to the first compass, called （）during the Warring States Period.
A.wet compass
B.Si Nan
C.dry compass
D.navy compass
正确答案：Si Nan
According to ancient records, natural magnets were employed in China as direction-finding devices. This led to the first compass, called （）during the Warring States Period.
A.wet compass
B.Si Nan
C.dry compass
D.navy compass
正确答案：Si Nan