简支梁试验荷载工况一般应选取______。
A.跨中最大正弯矩工况
B.跨中最大负弯矩工况
C.支点最大正弯矩工况
D.支点最大剪力工况
参考答案:A,D
男,65岁。近2年来活动时气喘。查体:BP130/50mmHg,胸骨左肋第3肋间可闻及舒张早期叹气样杂音。与上述心脏病变相关的体征为()。
A.Ewart征
B.心尖部开瓣音
C.Austin-Flint杂音
D.Graham-Steell杂音
E.奇脉
Every year in September or October, the Mid-Autumn Festival _____ by the Chinese people all over the world. [ ]
A. is celebrated
B. celebrated
C. celebrates
D. was celebrated