下列物质互称为同系物是( )
A.O2和O3
B.HCOOH和CH3COOH
C.
D.CH3CH2CH2CH3和
答案:B
Experts__________that there will be some small earthquakes after a big one. [ ]
A. predict
B.magine
C.demand
D.suppose
浅孔爆破时,炮孔直径小于50mm,炮孔深度小于6mm。