《集团公司反违章禁令》中的危险作业是指什么？
参考答案：高处作业、用火作业、动土作业、临时用电作业、进入有限空间作业。
My father knows a lot about American culture, for he _____ there for 2 years, and then he returned home. [ ]
A. stays
B. stayed
C. would stay
D. have stayed
中医五行学说的基本概念是指
A．风、寒、暑、湿、燥B．脑、髓、骨、脉、胆C．金、木、水、火、土D．心、肝、脾、肺、肾E．阴、阳、精、气、血
