开间
参考答案：
一间房屋内一面墙的定位轴线到另一面墙的定位轴线之间的实际距离。我国目前大量建造的砖混住宅，住宅开间一般不超过3.3米。
Again and again the doctor _____ the crying girl, but he couldn't find out what was wrong with her.[ ]
A. looked over
B. looked after
C. looked for
D. looked out
Runnable接口中的抽象方法是（）。
A、start
B、stop
C、yield
D、run
