下列哪项引起右室压力负荷过重（）.
A.严重贫血
B.肺动脉瓣关闭不全
C.静脉回流量增高
D.肺动脉高压
E.三尖瓣关闭不全
参考答案：D
They ________ a certain amount of working experience through volunteer work.[ ]
A. attempted
B. accumulated
C. abandoned
D. accomplished
投资银行主要开展哪些业务种类（答案不少于5种）？
