问题 单项选择题

当二极管外加电压时,反向电流很小,且不随()变化。

A、正向电流

B、正向电压

C、电压

D、反向电压

答案

参考答案:D

写作题

2012伦敦奥运会上,出现了很多令人喜欢而难忘的运动健将,其中叶诗文就是一朵游泳项目的奇葩。请根据提示,写一篇介绍她的短文。

叶诗文来自浙江,她16岁,她是一个很棒的游泳健将,在伦敦奥运会上,叶夺得了400米和200米个人混合泳金牌,并打破了世界纪录,创造了奇迹。

400m个人混合泳    400m individual women’s medley

                                                                              

                                                                              

                                                                              

                                                                              

                                                                               

                                                                              

                                                                                 

                                                                                 

单项选择题