心肌梗死
参考答案：是指在冠状动脉病变的基础上，发生冠状动脉血供急剧减少或中断，使相应的心肌严重而持久地急性缺血导致心肌坏死。
It was a______ that he was born on his mother’s birthday.
A．fact
B．satisfaction
C．coincidence
D．experience
已知{an}是等差数列，记bn=anan+1an+2（n为正整数），设Sn为{bn}的前n项和，且3a5=8a12＞0，则当Sn取最大值时，n=______．
