Read the passage below carefully and choose the correct answer a, b, c, or d.
The invention of the phonograph happened quite a by accident. Thomas Edison moved to Menlo Park, New Jersey, in 1876, where he established an industrial research laboratory. There, Edison was working on a carbon telephone transmitter to improve the existing Bell telephone system.
In that laboratory a year later, Edison invented the phonograph while he was trying to improve a telegraph repeater. He attached a telephone diaphragm to the needle in the telegraph repeater; in this way, he was able to produce a recording that could be played back. After he made some improvements to the machine, he tested it. He recited ‘Marry Had a Little Lamb’ into the machine and played his voice back to a very surprised audience.
What was Edison working on when he created the phonograph?
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Lời giải:
Báo saiGiải thích: There, Edison was working on a carbon telephone transmitter to improve the existing Bell telephone system. => Ở đó, Edison đang nghiên cứu một máy phát điện thoại carbon để cải tiến hệ thống điện thoại Bell hiện có.
Tạm dịch: Edison đã làm gì khi tạo ra máy quay đĩa?
a. Một bộ lặp lại điện báo
b. Một màng chắn điện báo
c. Một bộ lặp điện thoại
d. Màng chắn điện thoại