题目

两个亲本的基因型分别为AAbb和aaBB，这两对基因按自由组合定律遗传，要培育出基因型为aabb的新品种，最简捷的方法是 A．杂交育种       B.多倍体育种      C.单倍体育种      D.单倍体育种 答案：A ---Whose case is it?    --- I’m not quite sure. But maybe it _______ Mr. White. A. belongs to     B. is belonged to     C. is belonging to    D. belonged to