flat long-slotted crosshead

例句：

1. 1. The flooris very flat and easy to clean.
   地板非常平坦，容易清洁。
2. 2. Thecar was parked ona flat surface.
   汽车停在一个平坦的表面。
3. 3. The table is flat enoughfor both of us to sit on it.
   桌子足够平坦，我们两个人都能坐上去。