23+43=66

50+50=100

tk nhé

Ảnh A'B' là ảnh ao

Đồng hồ trên chỉ

Read the following passage, and answer the questions that follow

Ohio

In 1878, Thomas Edison began serious research into developing a practical incandescent lamp and on October 14, 1878, Edison filed his first patent application for "Improvement In Electric Lights". In 1879 he created a successful incandescent light bulb. This was his hardest project – from 1877 to 1880, Edison and his assistants tried around 3000 experiments to perfect their light bulb design. By the end of 1880, Edison had produced a bulb that lasted 1500 hours. This discovery marked the beginning of commercially manufactured light bulbs and in 1880, Thomas Edison’s company, Edison Electric Light Company began marketing its new product.

When was Edison born?

A. in 1878

B. in 1847

C. in 1877

D. in 1500