毕昇活字印刷，为什么领先世界？

Bi Sheng lived in China about one thousand years ago. 毕昇生活在中国，大约一千年前。 Before him, people copied books by hand. 在他之前，人们手抄书。 Bi Sheng made clay into small word blocks. 毕昇用胶泥刻成一个个字块。 He put the blocks together to print pages. 他把字块排好版就能印书。 After printing, he could reuse the blocks. 印完字块还能拆下来再用。 This was four hundred years earlier than Europe. 这比欧洲早了整整四百年。