某区域主导风向角风频之和应()才可视为有明显主导风向。
A.≥30%
B.≥40%
C.≥45%
D.≥60%
参考答案:A
----Would you like to go shopping with me today or tomorrow?
----________ , I have nothing to do.
A.Neither
B.Either
C.None
D.All
外照射的主要防护方式是:时间防护、距离防护和屏蔽防护措施。