急性化脓性中耳炎引起急性乳突炎不是由于（）
A.机体抵抗力弱
B.致病菌毒力强
C.治疗处理不当
D.乳突为板障型
E.乳突气化不良
参考答案：D, E
四个互不相等整数的积为9，则和为 [ ]
A．9
B．6
C．0
D．﹣3
Games, often seen as ____ activity for children, are still important in ____development of teenagers. [ ]
A. the: the
B. an; the
C. an; /
D. the; /
