隧道洞内渗水是指衬砌表面有象冒汗一样的细微水珠，使衬砌呈湿润现象。
参考答案：对
Why not _______ an English club to practice speaking English _______?
A. join in, as much as possible
B. join, as much as possible
C. join, as more as possible
窦房结位于（）与（）交界处的心外膜深面。
