毛利是经销商利润评价的关键,也是考核服务顾问绩效的结果性指标
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What relationship is material science mainly used to study?
A. the structures and components of materials
B. the structures and properties of materials
C. the components and properties of materials
D. the properties and applications of materials
Which option belongs to the electrical properties of the material?
A. electrical conductivity
B. heat capacity
C. thermal conductivity
D. elastic modulus
Which options belong to the mechanical properties of the material?
A. stiffness
B. dielectric constant
C. strength
D. toughness
Which options belong to the optical properties of the material?
A. electromagnetic
B. reflectivity
C. index of refraction
D. light radiation
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