主动脉瓣区相对性收缩期杂音可见于
A．健康儿童或青少年
B．二尖瓣狭窄
C．先天性肺动脉瓣狭窄
D．主动脉粥样硬化
E．房间隔缺损
参考答案：D
287-（187-45）=287-187+45．______．
In Switzerland, people ________ visit a friend’s house. [ ]
A. make plans
B. make plans to
C. makes plans to
D. make a plan
