预应力混凝土按施工方法可分为先张法预应力混凝土结构与后张法预应力混凝土结构。( )
参考答案:对
在△ABC中,AB=AC,AB的垂直平分线与AC所在的直线相交所得到锐角为50°,则∠B等于( )或( )度。
It is acknowledged that ________ shortest distance between persons is ________ sincere smile.
A.a;the
B.the;a
C.a;/
D.the;/