三尖瓣位于
A．右心房出口B．左心房出口C．右心室出口D．左心室出口E．右心房入口
参考答案：A
解析：三尖瓣位于右心房出口。
—Mike，you've got so many beautiful stamps.
—Yeah. I _______ collect stamps when I was 8 years old.[ ]
A. was used to
B. used to
C. am used to
D. used
简述道德情感的概念。
