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