胸骨右缘第二肋间触及收缩期震颤，最可能的是（）

A.室间隔缺损

B.动脉导管未闭

C.肺动脉瓣狭窄

D.主动脉瓣狭窄

E.二尖瓣关闭不全

Directions:

Write an essay of about 160-200 words based on the following drawing. In this essay, you should:

1) describe the pictures briefly,

2) interpret the meaning, and

3) give your comment.