问题 单项选择题

8051单片机的工作频率为12MHz,其内部定时器的最大定时时间是()。

A.256μS

B.8192μS

C.65536μS

D.131072μS

答案

参考答案:C

材料分析题

北京有位中学生在课堂上得知废旧电池对土壤和水体产生的严重危害后,就利用假期到处收集废旧电池,最远的地方是在父母的陪同下前往西藏收集。几年间他共回收废电池3万多节。后来他在北京的青少年中发起了一个回收废电池志愿者活动,号召北京市的青少年自觉回收电池,为环境保护作贡献。

(1)你怎样评价这位中学生的行为?

                                                                                                                                                            

                                                                                                                                                             

(2)以下两小题选做其中一题:

A、请说说你参加过哪些公益活动?有什么体会?

                                                                                                                                                             

                                                                                                                                                              

B、如果你没有参加过公益活动,请你谈谈参加公益活动的重要性以及今后你的打算。

                                                                                                                                                             

                                                                                                                                                             

单项选择题