急性心肌梗塞发生心律失常最多见于（）
A．发病后24h内
B．发病后30h左右
C．发病后36h左右
D．发病后48h
E．发病后72h
参考答案：A
在△ABC中，∠C=90°，DE垂直平分斜边AB，分别交AB、BC于D、E，若∠CAE=∠B+30°，求∠AEC．
The motivation for entering into a swap agreement is that:()
A. it provides firms that face financial risks with a flexible way to manage that risk.
B. it provides firms that face financial risks with a fixed way to manage that risk.
C. it gives you an ability to swap amongst a diverse range of products.
