摘要:19.如图所示.电源电压U及电阻R1均为恒定值.当与R1 串联的可变电阻R2分别被调为8Ω和2Ω时.可变电阻R2的功率都是2W.则R1的阻值为 Ω.电源先后供给电路的功率之比为 .

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书面表达(共1小题,满分25分)
假如你是高中三年级的学生李华,你在学校组织了一项“有烦恼向谁说”的调查活动。请用英语给报社编辑写一封信,反映相关情况。内容包括:调查结果(如图所示)、持相应想法的理由及你对调查结果的看法。

注意:1. 信的开头和结尾已经给出。
2. 词数120词左右。
Dear Editor,
I am a Senior Three student. Recently we have carried out a survey — “To whom do you do when in trouble?” The results are as follows.
                                                                     
                                                                    
                                                                    
                                                                     
                                                                    
                                                                    
                                                                      
Yours sincerely,
Li Hua

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