[9급 국가직 영어 2022년 8번]

To find a good starting point, one must return to the year 1800 during ① which the first modern electric battery was developed. Italian Alessandro Volta found that a combination of silver, copper, and zinc ② were ideal for producing an electrical current. The enhanced design, ③ called a Voltaic pile, was made by stacking some discs made from these metals between discs made of cardboard soaked in sea water. There was ④ such talk about Volta’s work that he was requested to conduct a demonstration before the Emperor Napoleon himself.