题目

四个塑料小球，A和B互相排斥，B和C互相吸引，C和D互相排斥．如果D带正电，则B球的带电情况是（   ）                                                                                                                               　   A． 带正电                      B． 带负电 　   C． 不带电                      D．    可能带负电或不带电                                                                                                                                     答案：B

查看本题答案和解析