求翻译：单孔式喷油嘴的喷油孔径多数为φ1.0、φ1.5毫米；多孔式喷油嘴的喷油孔径为0.25～0.40毫米。在清理这种小喷孔时，必须使用专用通针。常用的通针直径规格为φ0.25、φ0.30、φ0.35、φ0.40毫米。可以轻轻砸扁通针的末端或磨成450的沟槽形，以便较容易地清理喷孔。是什么意思？

The majority of single-hole injector fuel injection aperture for φ1.0 φ1.5 mm; porous injector fuel injection aperture of 0.25 to 0.40 mm. Clean up such a small nozzle, you must use a special pass needle. Commonly used needle diameter size φ0.25, φ0.30 φ0.35, φ0.40 mm. Gently flatten through the end