由折射率大的媒质射到折射率小的媒质的界面时，全部被反射回原媒质内的现象称为（）。
参考答案：全反射
石膏制品的物理性能有( )。
A．堆密度大 B．保温、绝热性能差C．吸音性强 D．抗冻性和耐水性好
As a unique variation of American literary realism, local colorism makes American literature a different. Who is the most famous local colorist What are local colorists most concerned
