右心衰引起呼吸困难是由于
A．肺顺应性降低B．缺氧及酸性代谢物积聚C．肺扩张及收缩受限D．肺泡内张力增高E．肺毛细血管不易换气
参考答案：B
— How did you do on the driving test?
— Not so well. I _____ much better but I was too nervous. [ ]
A. would do
B. could have done
C. must have done
D. should do
治疗军团菌病的首选药物是（）。
A．麦迪霉素
B．红霉素
C．土霉素
D．多西环素
E．四环素
