A:who; who
B:that; which
C:who; that
D:who; which
激光全息照片的底片上记录了光的干涉条纹,含有被摄物体反射的光的所有信息,实现了照片的立体性.若照相时,被摄物体被挡住一部分,通过调整视线仍可看见被挡部分;照片被切开成两半,从一半上仍可看到物体的全像,照片仅像一个观察物体的窗口。激光全息照相利用了激光____的性质。
A blue whale can weigh ____ ____ ____ 120 tons.
— ________ are they doing?
— They're ________.