下图表示甲、乙两种遗传病的谱系,其中Ⅱ-1的双亲正常,但其妹妹是乙病患者,Ⅲ-4表示相关基因纯合时导致胚胎死亡。据图回答:
Ⅱ-4的基因型是()
参考答案:AaBb
On hearing the news of the accident in the coal mine , she pale. [ ]
A.got
B.changed
C.went
D.appeared