加速器和钴-60治疗机治疗室土建设计中安全系数通常取()
A.1倍
B.1~2倍
C.2~5倍
D.5~7倍
E.7~9倍
参考答案:C
下列各项中,与皮肤散发热量有直接关系的结构是 [ ]
A.毛发和指甲
B.汗腺和血管
C.神经末梢
D.黑色素细胞
Jack is good, kind, hard-working and intelligent. ______, I can’t speak too highly of him.
A. As a result B. By the way C. In a word D. On the contrary