题目

两根完全相同的金属导体，如果把其中的一根均匀拉长到原来的4倍，把另一根对折绞合起来，则它们的电阻之比为                                                                                              ．                                                                                                                                  Smith insisted that the headmaster ________present at the meeting.A.wasB.beC.to beD.ought to