Yesterday we ____________ a lot of Christmas gifts. [ ]
A. buy
B. bought
C. buying
答案:B
的士临时停靠点白色框线
下列瓣膜病,出现水冲脉的是()
A.肺动脉瓣狭窄
B.二尖瓣狭窄
C.二尖瓣关闭不全
D.主动脉瓣狭窄
E.主动脉瓣关闭不全