紫菀、款冬花均可（）
A.清热止咳化痰
B.敛肺止咳化痰
C.泻肺止咳化痰
D.润肺止咳化痰
E.宣肺止咳化痰
参考答案：D
They did everything in their power to save the building dating back to the Qing Dynasty, but their efforts were _______.
A．in turn
B．in time
C．in vain
D．in need
发动机的故障诊断
