问题 单项选择题

活塞环的密封作用和寿命与()有关。

A.材料

B.制造方法

C.使用

D.环的径向压力分布

答案

参考答案:D

判断题
材料分析题

(1)你知道我国现行基本经济制度是什么?并指出坚持这一制度的依据。

                                                                                                                                                              

                                                                                                                                                              

(2)现阶段我国的是如何对待非公有制经济发展的?

                                                                                                                                                              

                                                                                                                                                              

(3)上图反映的内容是否全面?若有不足,请你完善它。(注:请用文字说明)