小明同学对串联电路电压规律进行了探究【猜想与假设】串联电路总电压等于各用电器两端的电压之和

【设计与进行实验】（1）按图所示的电路图连接电路．

（2）闭合开关，用电压表测出L₁两端的电压，并将数据记录表（3）仿照（2）分别测出BC和AC两端的电压，并将数据记录表

过分析表实验数据，小明得出结论：串联电路的总电压等于各用电器两端电压之和．小明的实验存在着一些错误，请你根据小明整个实验过程，指出小明实验中的错误是：

    Everyone has a family name. In China, the family name is the first name, but in English countries(国家)the family name is the last name. Do you know how English people get their family names? And what do they mean(意味着)? English people usually get their family name in these ways (方式).

    Some family names come from the places(地方)of their homes. A man live(住)on or near a hill, his family name may be (可能是) Hill. In England(英国), people's names may be Wood, Lake because they live near the wood or the lake.

    Some family names come from a person's job(职业). If a man is a cook, his family name may be Cook.

    And many people get their family names from their father's family names. If you hear(听到) the name "Jackson", you can know that he is the son of Jack.

绿色植物是生态系统的（　　）

李伯伯要修23张凳子，已经修好了3张，还要修____张凳子。