中国科技对世界的贡献

哪一个不是现代中国的四大发明？

In which dynasty did Cai Lun improve the papermaking technique?

Into which two stages can ancient Chinese printing techniques be divided?

Why did the variety of paper increase during the Sui and Tang Dynasties? Because which technique was popular?

造纸术是由哪个人改进的？

哪一个不是古代中国的四大发明？

造纸术最早传到日本是通过哪个国家？

Besides being used for writing and painting, what else was paper used for later?