有主次梁的楼板垂直施工缝应留设在次梁跨度中间的（）范围内。
A.1/2
B.1/3
C.2/3
D.1/5
参考答案：B
A good advertisement, _____ people attach positive meanings, can contribute to the sales of a product．
A．for which
B．to which
C．of which
D．on which
数控铣削刀具选择：刀具直径大小的选择要满足R刀具≤（）。
