Why don't we go to the park together?

1. I don't feel like it.
2. I'm sorry,but I can't.
3. I'm sorry I can't.
4. Sorry I can't.
5. Sorry, but I can't.
6. I'm afraid I can't.
7. I'm afraid, but I can't.
8. Afraid I can't.
9. I'm afraid that I can't.
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There seem to be many answers to the question. Would you check the possible answers? Which ones are grammatically wrong? Check them, please. Thank you for your help...

All seem fine except #7. That wouldn't be used.

#3 needs a period in it. #3 is made up of two very short sentences.

Sure! Let's check the possible answers and determine which ones are grammatically incorrect:

1. I don't feel like it. - This answer is grammatically correct.
2. I'm sorry,but I can't. - This answer is grammatically incorrect. The word "but" should be followed by a complete sentence.
3. I'm sorry I can't. - This answer is grammatically correct.
4. Sorry I can't. - This answer is grammatically incorrect. It's missing the subject before the verb "can't."
5. Sorry, but I can't. - This answer is grammatically correct.
6. I'm afraid I can't. - This answer is grammatically correct.
7. I'm afraid, but I can't. - This answer is grammatically correct.
8. Afraid I can't. - This answer is grammatically incorrect. It's missing the subject before the verb "can't."
9. I'm afraid that I can't. - This answer is grammatically correct.

So, answers 2, 4, and 8 are grammatically incorrect. The other answers are all grammatically correct ways to decline the invitation to the park.