静定平面刚架常见的形式有（）。
A.悬臂刚架
B.简支刚架
C.双铰刚架
D.三铰刚架
E.组合刚架
参考答案：A, B, D, E
"Not all of the snakes were dangerous." this means _________.
A．none of the snakes were dangerous
B．all of the snakes were not dangerous
C．few of the snakes were dangerous
D．no snakes were dangerous
箍筋的锚固弯钩端头直段长度不小于（）。
A.50mm或5d
B.50mm或6d
C.60mm或5d
D.60mm或6d
