按其内容和功用的不同,可将常用的通知分为以下几种:(1)()性通知;(2)()性通知;(3)()性通知;(4)()性通知。
参考答案:批示;指示;告知;任免
About ______ of these books ______ sold out. [ ]
A. two thirds; have
B. two thirds; has
C. two third; have been
D. two third; has been
软岩称为不稳定岩石,其强度定义为:单向抗压强度小于()的岩石。
A.15MPa
B.25MPa
C.35MPa