就辐射危害程度来说，外照射时，γ>β>α，内照射时，则α>β>γ。
参考答案：对
He was looking impatient at the visiting salesman, who showed no signs of getting ready to leave.
A．patient
B．patience
C．impatience
D．impatiently
具排钠利尿作用（）
A.多巴胺
B.麻黄碱
C.两者均是
D.两者均否
