2 Bibliography of Clothing Materials, edited by Wang Gehui, China Textile Publishing House, 2006; Functional Fibers and Textiles, edited by Zhang Mei, Jilin Science and Technology Press, 2008;
There is no requirement for CET-4 and CET-6.
4 It's average in Jida, but it's particularly unpopular. Few people take the exam, and they can basically get on the lowest line.
Good luck. Come on.