流感嗜血杆菌根据产生吲哚等生化反应分型
A．可分2个生化型B．可分4个生化型C．可分12个生化型D．可分8个生化型E．可分20个生化型
参考答案：D
He lost both of his parents in the big earthquake,but ________ for him,a kind couple adopted him
and took good care of him . [ ]
A. suddenly
B. naturally
C. obviously
D. luckily
在燃料量不变的情况下，汽压升高时，蒸汽流量（）。
A.增加
B.减少
C.不变
D.忽增、忽减
