Visual Foxpro的索引类型有（）。
A.查询索引
B.主索引
C.候选索引
D.唯一索引
E.普通索引
参考答案：B, C, D, E
We ________the difficulty together, but why didn't you tell me? [ ]
A. should face
B. might face
C. could have faced
D. must have faced
1999年世界卫生组织规定的高血压标准是
A．血压≥140/90mmHg
B．血压≥160/95mmHg
C．收缩压＞140mmHg
D．舒张压＞90mmHg
E．收缩压≥160mmHg
