风湿性心脏病二尖瓣狭窄，最严重的并发症是（）
A.肺水肿
B.咯血
C.心房颤动
D.心力衰竭
E.肺部感染
参考答案：A
The doctor advised her to wear flat shoes________her back problem.
A．on account of
B．in terms of
C．for lack of
D．on top of
