下列选项中符合线性规划模型标准形式要求的有()
A.目标函数求极小值
B.右端常数非负
C.变量非负
D.约束条件为等式
E.约束条件为“≤”的不等式
参考答案:B, C, D
33.The information________in the documents proved that my husband had been out of town in his car that day.
A.included
B.to include
C.include
D.include
维生素B12缺乏,有神经系统表现,维持治疗的时间为()。
A.酌情停药
B.完全消失
C.无原发病
D.终生
E.半年到1年