工程建设项目设计招标文件编制过程中必须遵循( )的原则。
A．专业性
B．全面性
C．突出性
D．准确性
E．灵活性
参考答案：A,B,D,E
— I don't know what to buy for my mother.
— If I ____ you. I ____ a bund of flowers. [ ]
A. am; will buy
B. were; would buy
C. am; would buy
具有预防龋齿发生的营养素是（）。
A.氟
B.磷
C.铁
D.铜
E.锌
