下列哪项不是急性心肌梗死的诱因(    )
   A．饮餐    B．睡眠    C．情绪激动    D．重体力活动    E．外科手术

单项选择题______, there was no hope of her being able to sleep. A．As she was exhausted B．Exhausted as she was C．Exhausted as was she D．As was exhausted she

单项选择题设f(x)在(a，b)内有连续的二阶导数，x0∈(a，b)，若f(x)满足( )，则f(x)在x0取到极小值。 A．f(x0)＞0，f(x0)=0 B．f(x0)＜0，f(x0)=0 C．F(x0)=0，f(x0)＞0 D．f(x0)=0，f(x0)＜0