PH/HS Tham Gia Nhóm Lớp 10 Để Trao Đổi Tài Liệu, Học Tập Miễn Phí!
The Chinese (1) in-- the first compass sometime between the 9th and 11th century; it
was made of lodestone, a naturally-magnetized iron ore, the attractive properties of (2)
they had been studying for centuries. (Pictured is a model of an ancient Chinese
compass from the Han Dynasty; i ...