345678三边等于15简介:The assessment is divided into three levels. The first level is the understanding of various materials. Not only the name of the material, but also the origin and performance of the material must be stated. As much as possible, the more detailed the better.
The assessment is divided into three levels. The first level is the understanding of various materials. Not only the name of the material, but also the origin and performance of the material must be stated. As much as possible, the more detailed the better.