This addon follows the same restrictions as the main DeepL site (length limits), but it's a nice and quick way to pull up a translation.

運作正常，如果開啟是在背景標籤就更好了

After using Google Translate for years, I am IMPRESSED! DeepL's translation appear to be more accurate than Google's. Also when 'listening' to the translations, DeepL's speech is slower so the proper pronunciation of each word can be understood. Google's speech is so fast (even at the slower level) that you cannot hear the proper pronunciation.