13号、13A型钩尾框后端上、下弯角处在（）范围内，须进行湿法磁粉探伤。
A、20mm
B、30mm
C、40mm
D、50mm
参考答案：D
看图，完成句子。
1. There are ____________ people in Alice's family. Alice and Ann ____________ twin sisters.
2. Every evening, Alice ____________ newspapers. Her sister Ann ____________ cartoons on ____________.
3. Every morning, Alice ____________ to school by ____________, but Ann ____________ ____________
____________ on ____________.
假设检验的步骤不包括
A．对总体参数作出区间估计B．建立检验假设，确定检验水准C．计算检验统计量D．选定检验方法E．确定户值，根据户值作出推断结论
