Chinanews, Beijing, July 21 - Nowadays, the staff members of post offices in Beijing are busy sending various textbooks of Chinese language and culture to countries all over the world. Learning Chinese language has become a fashion.It is estimated that everyday 200 thousand such textbooks are mailed outside China. On the busiest day, the staff members in the International Post Office in Beijing handled 6 tons of textbooks.This year, the Chinese language fever is building up to a high pitch. The number of entrants for HSK (Chinese language proficiency test) has leapt to 35,000, a new high, while the figure in 1991, when the first test was held, was only 39.