Johann Gutenberg, who worked as a goldsmith  , took what had already been discovered, and created a small invention that changed history. He created a machine that allowed him to move small blocks of letters in such a way that written material could be printed and mass-produced. Few people could read before Guttenberg made the invention, but once books became less expensive, more Europeans could read and write. Block printing existed long before Gutenberg. The Chinese had been using wood blocks to print books as early as 868, but a new set of woodcuts   had to be made for each book. Producing one book was not easy; producing all kinds of books was more difficult. Writing ink dates from about 2500 BC in Egypt and China. Gutenberg used an oil-based printing ink that would last longer than other inks used in his time. We don't know much about Gutenberg because he was not famous during his lifetime. He was born in Germany about 1400. In 1448, Gutenberg developed signatures for each number, letter, and punctuation mark  . He then built the molds   to hold the signatures in place. Gutenberg published the first mass-produced book: a 1,282 page Bible. To this day, more copies of the Bible have been printed than any other book. Copies of Gutenberg's invention spread throughout Europe, but the German goldsmith did not get rich from his invention. Some officials _ the invention of printing because they feared that it would spread bad ideas. By 1500 there were 1,700 printing presses in Europe. The presses had already produced about 20 million volumes   of 40,000 different books. Compared with block printing in China, Johann Gutenberg's method   _  .
was difficult to run needed harder paper used a new kind of ink was put into use earlier
Question: Johann Gutenberg, who worked as a goldsmith  , took what had already been discovered, and created a small invention that changed history. He created a machine that allowed him to move small blocks of letters in such a way that written material could be printed and mass-produced. Few people could read before Guttenberg made the invention, but once books became less expensive, more Europeans could read and write. Block printing existed long before Gutenberg. The Chinese had been using wood blocks to print books as early as 868, but a new set of woodcuts   had to be made for each book. Producing one book was not easy; producing all kinds of books was more difficult. Writing ink dates from about 2500 BC in Egypt and China. Gutenberg used an oil-based printing ink that would last longer than other inks used in his time. We don't know much about Gutenberg because he was not famous during his lifetime. He was born in Germany about 1400. In 1448, Gutenberg developed signatures for each number, letter, and punctuation mark  . He then built the molds   to hold the signatures in place. Gutenberg published the first mass-produced book: a 1,282 page Bible. To this day, more copies of the Bible have been printed than any other book. Copies of Gutenberg's invention spread throughout Europe, but the German goldsmith did not get rich from his invention. Some officials _ the invention of printing because they feared that it would spread bad ideas. By 1500 there were 1,700 printing presses in Europe. The presses had already produced about 20 million volumes   of 40,000 different books. Compared with block printing in China, Johann Gutenberg's method   _  .
A. was difficult to run
B. needed harder paper
C. used a new kind of ink
D. was put into use earlier
Answer: