话音信道拥塞率（不含切换）＝（）×100％
参考答案：忙时话音信道溢出总次数（不含切换）/ 忙时话音信道试呼总次数（不含切换）
The family as well as their dog________on the roof by the flood. [ ]
A. was trapped
B. trapped
C. were trapped
D. trapping
