A、In 1848. B、In 1858. C、In 1868. D、In 1878. C预览选项可知，本题考查时间，故听音时要留意短文中出现的相关时间。文中明确提到Edison’s first invention…in 1868，故答案为C)。

Edison is a well-known American inventor. He was taught by his mother when he was a child. Later he learned things by himself by reading and experimenting. He built a lab for himself to work in, and he worked very hard in his sixty years of scientific activities. He made over a thousand inventions. Few inventors in the world could have such great success. Edison’s first invention was made in 1868. He was then a telegraph operator. He wished to work out a new method to improve the old telegraph system because it was impossible at that time for the system to send more than one message along the same line at the same time. He read all the works of Faraday, another great scientist, before starting his invention. Sometimes he didn’t go to bed and didn’t even stop to eat. He thought he had very much to do and there was no time to lose. Days and nights he was reading and reading. After he read through Faraday’s writings, he began his experiments. A few months later he succeeded in building a double transmitter and improved the old telegraph system.
Questions 33 to 35 are based on the passage you have just heard.
33. What can we learn about Edison’s early education?
34. When did Edison make his first invention?
35. Why did Edison decide to improve the old telegraph system?