— _____________ that woman, Helen?

— She's Miss Li.

— _____________ is that dress? Is it hers?[ ]

A. Who, Whose

B. Whose, Who's

C. Who's, Whose

放射治疗中X线半价层用于表达()

A．X射线的强度 

B．X射线的能谱 

C．X射线的穿透能力 

D．X射线的平均能量 

E．X射线的百分深度剂量