人体由80多种元素组成。根据元素在人体内的含量不同，可分为宏量元素和微量元素两大类。

患者，男，56岁，肝硬化病史4年，1个月前出现腹胀，腹围增加，3d前突然出现剧烈腹痛、发热，腹胀加重，并排出少许暗红色血便，最可能的诊断是

A．食管静脉曲张破裂出血

B．自发性腹膜炎

C．合并消化性溃疡急性穿孔

D．门静脉血栓形成

E．上消化道出血

物业管理企业资质等级分为( )。

A．国家级、省级、地市级

B．甲级、乙级、丙级

C．一级、二级、三级

D．高级、中级、初级

Both bus and tree topologies are characterized by the use of multipoint （） . For the bus, all stations attach, through appropriate hardware （） known as a tap, directly to a linear transmission medium, or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received fromthe （） . A transmission from any station propagates the length of the medium in both directions and can be received by all other （） . At each end of the bus is a （） , which absorbs any signal, removing it from the bus.

Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received fromthe（）.

A．tree

B．bus

C．star

D．ring

红帽Linux企业版提供了一个自动化的基础架构，包括______、身份管理、高可用性等功能。

下列各项不见于典型心绞痛的是

A．多为夜间发作突然惊醒
B．中段胸骨后压榨性疼痛
C．含服硝酸甘油5min可缓解
D．可放射至左肩左臂
E．心电图ST段压低