principle of choosing materials

• 选材

principle of choosing materials的用法和样例：

例句

1. High-class tonics are prepared from superior materials.
   上等补晶，选材精良。
2. Proper selection of materials, preheating and postheating can help to avoid cracking.
   适当的选材与低温预热及后热可以抑制表面裂纹的产生。