题目

小灯泡通电后其电流I随所加电压U变化的图线如图所示，P为图线上一点，PN为图线过P点的切线，PQ为U轴的垂线，PM为I轴的垂线。则下列说法中正确的是（  ） A．随着所加电压的增大，小灯泡的电阻增大 B．对应P点，小灯泡的电阻为R＝ C．对应P点，小灯泡的电阻为R＝ D．对应P点，小灯泡的功率为图中矩形PQOM所围的面积Rewrite the following sentences as required. (根据所给要求，改写下列句子，每空格限填一词)【小题1】Lily had a good time during her stay in Beijing. (改为否定句)Lily ________ ________a good time during her stay in Beijing.【小题2】We have a class meeting once a week. (对划线部分提问)_________ _________ do you have a class meeting?【小题3】Many countries make laws to stop smoking in public. (改为被动语态)Laws _________  _________ by many countries to stop smoking in public.【小题4】The river pollution is serious in our country today. (改为感叹句)_________ _________ the river pollution is in our country today!【小题5】Robert is so short that he can’t yet reach the pears on the table. (改为简单句)Robert isn’t _________ _________ to reach the pears on the table.【小题6】I can’t give you better advice than that. (保持原句意思)I can _________ give you _________ advice.【小题7】Bill didn’t go to bed until he finished writing the letter at 11:45 last night. (保持原句意思)Bill _________ _________until he finished writing the letter at 11:45 last night.