各类防雷建筑物应采取防直击雷和防雷电波侵入的措施。( )
参考答案：对
具有养血敛阴、平肝止痛功效的药物是（）
A.白芍
B.赤芍
C.当归
D.何首乌
E.阿胶
It _____ more than half a year since I _____ a teacher. [ ]
A. is, become
B. was, become
C. is, became
D. has been, becomes
