一对正常夫妇生了“龙凤双胞胎”,其中男孩色盲,女孩正常。则此夫妇的基因型为()
A:XbY,XBXB
B:XBY,XbXb
C:XbY,XBXb
D:XBY,XBXb
The movie covers all of Chinese history. It is _________ worth seeing again.
用一平面去截下列几何体,其截面可能是长方形的有( )