This is the one I really wanted.

很棒的翻译

Ótima extensão

有个使用上的小问题，当在一个新的页面中，右键菜单中没有翻译的选项，只能从地址栏中点翻译，之后右键菜单栏中才会出现翻译选项

要vpn，功能还行

Installed, but the button to translation is nowhere to be found. Restarted my Firefox, restarted my laptop. Unfortunately, this ads-on appears to be non existing.
UPDATE: It's 80.0.1 (64 bit). But actually while searching for that information I've found out that I am using anonymous browsing, which was blocking the add-on.
All is well now, I am changing the stars. Also I do appreciate your concern. Thank you.

非常好，终于找到个个人十分满意的翻译器，不用跳转就可以直翻网页，就和在谷歌上使用翻译的感觉一样。

This is what I was missing in Firefox

目前最棒的翻译扩展

Perfectly!