本发明公开了一种制备方法 英语怎么说，谢谢

This invention has published a new producing method.(既然是发明，这个方法就是新的方法，需要把隐含的特点翻译出来)

A production method is opened in this invention.

This contrivance makes a manufacturing technique known to the public.

This invention has published a producing method.