肝硬化患者全血细胞减少最主要的原因是
A．营养吸收障碍
B．脾功能亢进
C．骨髓造血功能低下
D．上消化道出血
E．肝肾综合征
参考答案：B
It was the first time Mary _____ such a big opening ceremony.
A．has attended
B．attended
C．had attended
D．should attend
如何区分债券的正回购和逆回购
