以下哪一种是后天二尖瓣狭窄的病因？（）
A.高血压性心脏病
B.冠心病
C.扩张型心肌病
D.风湿性心脏病
E.法洛氏四联症
参考答案：D
It is surprising that Jack, who is only 39 years old, _______ in the field of engineering for 20 years when he entered the company last month.
A．worked
B．had worked
C．has worked
D．working
《先醒斋医学广笔记·吐血》中提出了著名的治吐血三要法是
A．行血、补肝、降气
B．补气、止血、补肝
C．补气、补血、宁血
D．降气、宁血、止血
E．行血、通络，、止血
