The Chinese invented block printing more than 1, 400 years ago. The original characters were carved on wood and ink was then applied. Block printing is time consuming and (cost) a lot of manpower and materials. Misprinted characters cannot be (easy) corrected. These shortcomings were only overcome after the appearance of movable type printing, greatly improved the speed and quality of printing.
Bi Sheng of the Northern Song Dynasty invented the movable type printing. He carved the Chinese characters on small (cube) of sticky clay. He baked them in the fire until they became hard and movable. In the course of presswork, the movable characters were placed into , iron frame until it was full. He then took a smooth board and pressed it over the surface so that the block of type became even: Then ink was applied and it was ready printing. To be more (efficiency), he prepared two iron boards. When one was being used for printing, the other could be used (put) characters in order for the next page. The two boards were used alternately.
Although what Bi Sheng invented was simple when (compare) to today's letterpress printing; it already bad the main traits of modem printing. So Bi Sheng's (contribute) to printing cannot be overstated.
