元素Z的核电荷数为a，它的阳离子Zm+与元素Y的阴离子Yn-的电子层结构相同，则元素Y的核电荷数是_________。
a-m-n
We couldn't eat in a restaurant because _____ of us had _____ money.
[ ]
A. all; no
B. any; no
C. none; any
D. no one; any
圆钢与圆钢、圆钢与钢板间的角焊缝有效厚度不宜小于圆钢直径的（）倍。
A.0.1
B.0.2
C.0.5
D.0.75
