慢性支气管炎患者呼吸道感染时,最常致病的革兰阴性杆菌为()
A.流感嗜血杆菌
B.大肠埃希菌
C.肺炎克雷伯杆菌
D.铜绿假单胞杆菌
E.变形杆菌
参考答案:A
By the time I got to school, I realized that I ______ my pen at home. [ ]
A. have forgotten
B. have left
C. had forgotten
D. had left
多效蒸发与单效蒸发的单位蒸汽消耗量e和加热蒸汽经济性E相比,()。
A.e较大,E较大
B.e较小,E较小
C.e较小,E较大
D.e较大,E较小