政府采购法的原则有（）
A.公开性原则
B.公平性原则
C.公正性原则
D.竞争性原则
E.科学性原则
参考答案：A, B, C, D
_________, I think, and the problems would be settled.
A．If you double your efforts
B．Making more efforts
C．So long as you don’t lose heart
D．A bit more effort
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