决策者面对（），其决策在于选择最大的收益或最小的支付的方案。
A.非确定型决策
B.选择型决策
C.确定型决策
D.风险型决策
参考答案：C
Bob thought he couldn’t go to the party because he had too much homework, but persuaded by his friends, he went _________.
A．above all
B．in all
C．after all
D．first of all
我国“神舟五号”载人飞船发射成功。它用物质M作为高能燃料，M燃烧的化学方程式为2M+O2N2+2H2O。则M的化学式是_____________________，推断的理由是_____________________。
N2+2H2O。则M的化学式是_____________________，推断的理由是_____________________。