单项选择题When we say somebody only goes to the library once in a blue moon, we imply that he seldom goes to the library.A.对B.错
单项选择题肝门管区不存在下列哪种结构 A、结缔组织 B、小叶间胆管 C、小叶下静脉 D、小叶间静脉 E、小叶间动脉