马呈梨形囊状的副性腺称（）。
A． * * 球
B．精囊腺
C．前列腺
D． * * 球腺
E．输精管壶腹
参考答案：B
The sunspot came into its active stage, ____ that happens once every eleven years.
A．one
B．it
C．the one
D．what
