相比而言，碳素钢中（）过热后更容易开裂。
A.低碳钢
B.中碳钢
C.高碳钢
D.中、低碳钢
参考答案：C
—Jimmy isn't here. Where is he?
—He hurt his arm on the playground just now. He ______ to the school doctor's.[ ]
A. has gone
B. has been
C. goes
我国保险代理机构可以采取( )组织形式。
A．个人独资
B．合伙无限责任公司
C．股份有限公司
D．无限责任公司
