某周期ⅡA族元素的原子序数为x,则同周期的ⅢA族元素的原子序数为[ ]
A.只能是x+l
B.可能是x+8或x+18
C.可能是x+2
D.可能是x+l或x+11或x+25
答案:D
—______ are the books about computers?
—They are ______ Shelf B. [ ]
A. How; on
B. Where; on
C. What;i n
圆锥破碎机的规格是用动锥直径来表示。