There ______________ a pen and two books on the desk. [ ]
A. is
B. are
C. was
D. were
答案:A
主动脉瓣狭窄引起心功能代偿最主要的是()
A.心脏节律改变
B.左心室肥厚
C.回心血容量增加
D.左心室腔扩大
E.右心房扩张
维生素D缺乏性佝偻病骨的骨骼改变,因胸骨及相邻肋骨向前突出所导致的体征是()。
A.方颅
B.鸡胸
C.肋骨串珠
D.手镯征
E.脚镯征