虚警是指没有信号仅有噪声的，（）被误认为信号的事件。
参考答案：噪声电平超过门限值
_________ that the government can lead them out of the financial crisis, people are optimistic
about the future of the country.
A．Convincing
B．Convinced
C．To convince
D．Having convinced
总产量处于递增阶段时，边际产量：（）
A.递减
B.递增
C.为正
D.上述任何一种
