The upper side of the barrel body is provided with an observation cleaninghole; therefore, the cleaning is convenient and quick.
在筒体的上边设有观察清理孔，因而清理方便快速。
2
Sew or patch tears as soon as they happen. If the hole gets too big, clothing becomes cleaning rags.
哪里坏了一点就尽快的修补。要是这个洞变得太大，这个衣物就只能用作抹布了。
3
For this reason, the well designer generally seeks to maximize the fluid velocity (or other measure of jet energy) to achieve maximum cleaning at the bottom of the hole.