表兄妹结婚所生子女的近交系数是（）
A.1/4
B.1/8
C.1/16
D.1/32
参考答案：C
I can't send her an invitation. I wish I _______her new address. [ ]
A. know
B. will know
C. have known
D. knew
一座楼房，每层楼房之间有20级楼梯，一个人住在六楼，每次回家必须登上多少级楼梯( )
A．100
B．101
C．102
D．104
