当桥梁跨径在8~16m时,简支板桥一般采用()。
A.钢筋混凝土实心板桥
B.钢筋混凝土空心倾斜预制板桥
C.预应力混凝土空心预制板桥
D.预应力混凝土实心预制板桥
参考答案:C
Half of the students done most of the work. The rest of the work rather difficult. [ ]
A. have ; is
B. has ; are
C. have ; are
D. has ; is
强心苷(苷)对下列哪种原因所致的慢性心功能不全疗效较好()
A.甲状腺功能亢进
B.维生素B缺乏
C.严重二尖瓣狭窄
D.先天性心脏病
E.缩窄性心包炎