------Look at the black clouds. It soon. ------Sure, if only we out. A. is raining; didn’t come B. is to rain; won’t start C. will rain; haven’t started D. is going to rain; hadn’t come 答案:D
在探究串联电路的电压规律时,某同学使用的实验电路如图所示.他先用电压表正确地测量了灯泡L1两端的电压.为了测量灯泡L2两端的电压,他想将电压表接A点的那一段导线改接到电路中的C点,而保持电压表接B点的导线不动.你认为这种接法是________(选填“正确”或“不正确”)的,理由是________.