（）有时也被称为垢下腐蚀、沉积腐蚀、垫片腐蚀。
参考答案：缝隙腐蚀
As he pushed her, sitting on a swing, she ________ higher and higher. [ ]
A. swung
B. wandered
C. swept
D. whispered
简述多台阶集中排土的基本概念？
