胸部CT扫描,纵隔结构可显示的原因主要在于:()
A.大血管的存在
B.气管的存在
C.食管的存在
D.淋巴结的存在
E.脂肪组织的存在
参考答案:E
— Why do you do volunteer work in the North-West?
— I___ to improve the lives of the children there through my efforts.
A.was trying
B.have tried
C.am trying
D.tried
利他者的( )影响利他行为。
A.人格因素
B.心情
C.内疚感
D.责任和承诺