读一读,选一选
____ Is your father here today? A. No, I don't.
____ What does your mother do? B. He's a businessman.
____ Do you want to be a head teacher? C. No. He's in Australia.
____ What does he do? D. She's a head teacher.
白化病是由隐性致病基因控制的遗传病.一对肤色正常的夫妇生下了一个白化病孩子,那么这对夫妇的基因组成成分是( )