齿轮常用的热处理方法有（）。
A.表面淬火
B.渗碳淬火
C.调质
D.正火
E.渗氮
参考答案：A, B, C, D, E
Theme park owners _____ their profit ____ charging admission fees, ______ new brand athletic
equipment and selling souvenirs.[ ]
A. have; from; advertising for
B. make; by; advertising
C. gain; with; advertising
D. benefit; through; advertising for
列入项目后评价年度计划的项目单位，应当在年度计划下达后______个月内，向国家发改委报送《项目自我总结评价报告》。
A．3 B．4C．5 D．6
