It depends on the length (words), the quality of the original text, the professionalism of the content, the level of the polisher and the familiarity with the content of the paper. Generally speaking, if the quality of the original text is relatively high, it is no problem to complete 3000-5000 words a day. If there are many problems in the original text, it may only be 2000 words a day, which is also a completely normal speed.