在英语反意疑问句中，不定代词的使用取决于主句的肯定或否定。如果主句为肯定句，不定代词使用否定形式；如果主句为否定句，不定代词使用肯定形式。但对于某些不定代词，如nobody和nothing，其肯定形式与否定形式相同，反意疑问句的形式与主句相同。
不定代词包括somebody, anybody, nobody, everybody, something, anything, nothing, everything等。它们在反意疑问句中的用法与肯定句和否定句不同。
如果反意疑问句的主句为肯定句，不定代词要使用否定形式。比如：
- She knows somebody here, doesn't she?
- Anybody can do this, can't they?
- Everybody enjoyed the party, didn't they?
- Something is wrong with the computer, isn't it?
- Everything is going well, isn't it?
如果反意疑问句的主句为否定句，不定代词要使用肯定形式。比如：
- She doesn't know anybody here, does she?
- Nobody can solve this problem, can they?
- They don't have anything to eat, do they?
- You didn't see anything strange, did you?
- There is nothing wrong with the car, is there?
需要注意的是，有些不定代词的肯定形式与否定形式相同，如nobody和nothing。在这种情况下，反意疑问句的形式与主句相同。比如：
- Nobody knows the answer, do they?
- Nothing happened, did it?
