女性中枢性性早熟最常见的原因为（）
A.颅内肿瘤
B.特发性
C.原发性甲状腺功能减退症
D.肾上腺皮质增生
E.食用含有雄激素的食物
参考答案：B
They became friends again that day. Until then they ______to each other for nearly two years.
A．didn’t speak
B．hadn’t spoken
C．haven’t spoken
D．haven’t been speaking
简述资本有机构成提高的途径。
