[音频]On the night before Christmas in 1818, an Austrian clergyman and a music teacher sang a song that they wrote together for the first time.They did not know it then, but their song would go on to be the world's most famous Christmas carol.The song is called, in English, "1.______ Night."Joseph Mohr, a young clergyman from Salzburg, first wrote the words for a poem in 1816. Two years later, Mohr asked Franz Xaver Gruber, his friend and a teacher from Upper Austria, to write music for the words. Gruber 2.______ added some musical notes to the poem. He did not attach much importance to the piece.On December 24 of that year, these two men sang the song for the first time at the St. Nikola Church in Obendorf, 3.______ of Salzburg. The church's organ was not working. So, they played the music with a guitar-like 4.______.A new hit song was born. Singing families then carried the song to the rest of Austria and across 5. ______.American clergyman John Freeman Young published the first English 6. ______of the song in 1859 at Trinity Church in New York. His translation included the well-known words "sleep in heavenly peace."On Christmas Eve of 1914, a young British officer named Charles Brewer heard something that he had never heard before on the 7.______ – a Christmas song. German soldiers were singing the German words to "Silent Night." The words were not 8.______to Brewer -- but the music was.Once the German soldiers had finished their song, Brewer and his soldiers answered by singing the English version of "Silent Night" and other Christmas songs.By Christmas morning, along the 800-kilometer Western Front, German and allied soldiers came out of the trenches. They put down their 9.______ and exchanged greetings. The act became known as the World War I Christmas Truce.But it was not until American singer Bing Crosby 10. ______"Silent Night" in 1948 that the song became famous worldwide.