办理税务登记证需要的资料有（）。
A、法人代码证书副本
B、法人身份证复印件
C、公章、财务章
D、营业执照副本
参考答案：A, C, D
It was the third time that the boy _________ late. So his teacher got very angry.
A．have been
B．was
C．had been
D．was being
微分方程y″+3y′=sinx的阶数是______．
