基因型分别为aaBbCCDd和AaBbCCdd的两种豌豆杂交,其雌雄配子结合方式、子代中纯合子的比例分别为 ( )
____ + ____ = ____
— Sorry, I won't do it again.
函数y=1x+3自变量的取值范围是( )