1. I have fought with Bill and have felt sorry later.

(Is it correct?)

2. I have fought with Bill.
3. I have ever fought with Bill.
4. I fought with Bill and I feel sorry for that now.

(Does #2 mean #3 or #4?)

Only 2 and 4 are correct.

Thank you.

How about the following?

* I have fought with Bill before.

(is this correct?)

Yes. It's correct.

#2 does not necessarily mean the same as #3 or #4.

Here's the breakdown of each sentence:

1. "I have fought with Bill and have felt sorry later." - This sentence indicates that you fought with Bill and then felt sorry afterwards. It suggests that the feeling of remorse occurred in the past after the fight.
To check if it is correct, examine the tense use within the sentence. "Have fought" is in the present perfect tense, indicating an action that started in the past and has a connection to the present. "Have felt sorry" is also in the present perfect tense. The use of the present perfect tense suggests that the feeling of remorse is ongoing and has a connection to the present. So, in this context, the sentence seems grammatically correct.

2. "I have fought with Bill." - This sentence simply states that you have fought with Bill at some point in the past. It doesn't specify anything about feeling sorry or any specific time frame.
To determine its meaning, you need additional context or information.

3. "I have ever fought with Bill." - This sentence is grammatically incorrect. The word "ever" does not fit in this context. However, if we remove "ever", the sentence would become "I have fought with Bill." This then matches sentence #2, which means that you have fought with Bill at some point in the past.

4. "I fought with Bill and I feel sorry for that now." - This sentence indicates that you fought with Bill in the past and currently feel remorse or regret for your actions.
To confirm if it is correct, consider the use of tense. "Fought" is in the past tense, indicating that the fight happened in the past. "Feel sorry" is in the present tense, suggesting that the feeling of remorse exists currently. So, in this context, the sentence appears to be grammatically correct.

In summary, #2 simply states that you have fought with Bill in the past, without any explicit mention of remorse or regret. It can be understood differently depending on the context. #3 has incorrect grammar, but without "ever" it matches the meaning of #2. #4 explicitly mentions feeling sorry for fighting with Bill after the event occurred.