21.certificate on performance tests of packing 包装性能检验证书
performance n.(常与of连用)表现性能;能力;成绩，工作成果表演;扮演;演奏
Her performance in the play was very good.她在剧中的表演非常好。
The performances are on the 5th and 6th of this month.剧的)上演是在这个月的5号和6号。
packing n.包装, 打包; 装箱
22.certificate for doping silk classification and conditioned weight
双宫丝品级及公量检验证书
duping n.[纺]双宫丝
classification n.分类, 分级
account classification帐户(科目)分类
activity classification业务活动分类
conditioned weight n. 公量
23.certificate for raw silk classification conditioned weight 生丝品级公量检验证书
raw silk n.生丝
24.certificate for spun silk yarn quality 绢丝品质检验证书
spun silk n.绢丝
yarn n.纱, 纱线, 故事, 奇谈
quality n. -ties品质;性质转自:考试网 - [telnote.cn]
a watch of good quality品质好的手表
This new model is of high quality and is not expensive either.这种新型号质量非常好,而且也不贵。
a poor quality of cloth品质低劣的布料
qualities of leadership领导才能
25.certificate for thrown silk classification and conditioned weight 捻线丝品级及公量检验证书
thrown throw的过去分词
thrown silk 捻线丝
