单项选择题
A.梁底模应起拱,起拱高度为6mm B.梁底模应起拱,起拱高度为2mm C.梁底模应起拱,起拱高度为15mm D.梁底模不用起拱
A.0.5 B.1 C.2 D.3
A.60° B.90° C.135° D.180°