3. How many hours did the 1880 bulb last? A. 3000 B. 1500 C. 1880 D. 1878
Giải thích
3. Dẫn chứng “By the end of 1880, Edison had produced a bulb that lasted 1500 hours.”
Chọn B
3. Dẫn chứng “By the end of 1880, Edison had produced a bulb that lasted 1500 hours.”
Chọn B