筛板塔每层塔板的液面高度由（）决定。
A、无孔区
B、塔板开孔滤
C、溢流堰
D、降液管
参考答案：C
My grandma_____in the country. Now she in the city.
A．used to live, lives
B．used to living, lived
C．uses to live, is living
D．was used to live, lives
事故紧急停炉的处理方法有哪些？
