题目

已知某行星绕太阳公转的半径为r，公转周期为T，引力常量为G，由此可求出太阳质量的表达式为M=           ．                                                                                                                                                                                                                          Sir, you should__________ at the red light．--------Do you remember?A．stop B．have stopped C．not have stopped D．stopped