Here are other sentences I need to check. I really hope you can check them, Writeacher.

1) blamed my friend Peter for breaking some plates, but the real guilty was me.
I’m quite independent of my parents because I do a lot of things without their help.
2) I’m not independent because I’ m not working at the moment.
I once blamed a friend because he left my homework at home.
3) I last felt sorry for my best friend because he got a bad mark in history. I felt sorry when his little dog died during a fire. It was saving my friend’s sister when the fire killed.
4) I'm still dependent on my parents because I'm not of age.
5) I was last ashamed of myself when I told a lie.
I blamed my friend for not phoning me/because she didn't phone me/when she didn't phone me (when is a mistake).
6) I was last sorry for a person when he had an incident with his motorbike. (correction: I was last sorry for a friend of my when he had a motorbike accident).
7) Have you ever blamed a friend for something he/she didn't do? Yes, I have. I blamed my best friend for forgetting our meeting.
8) I got angry with her, but she was really sorry for it. So I decided to apologize to her.

1) I blamed my friend Peter for breaking some plates, but I was really the guilty person.

2) I’m not independent because I’m not working at the moment. <~~doesn't make sense!

3) ... It was saving my friend’s sister when the fire killed it.

6) I was last sorry for a person when he had an incident with his motorbike. (correction: I was last sorry for a friend of my when he had a motorbike accident). correction is good

Everything else is fine.

1) The sentence "blamed my friend Peter for breaking some plates, but the real guilty was me" contains an error. The word "guilty" should be "guilt" instead. The correct sentence would be "I blamed my friend Peter for breaking some plates, but the real guilt was mine."

2) The sentence "I’m not independent because I’ m not working at the moment" is grammatically correct and doesn't require any changes.

3) The sentence "I last felt sorry for my best friend because he got a bad mark in history. I felt sorry when his little dog died during a fire. It was saving my friend’s sister when the fire killed" needs some revisions. Firstly, there should be a period after the first sentence. Secondly, the sentence "It was saving my friend’s sister when the fire killed" is unclear and can be improved. The corrected sentence would be "I last felt sorry for my best friend when he got a bad mark in history. I also felt sorry when his little dog died in a fire while trying to save my friend’s sister."

4) The sentence "I'm still dependent on my parents because I'm not of age" is grammatically correct and doesn't require any changes.

5) The sentence "I was last ashamed of myself when I told a lie" is grammatically correct and doesn't require any changes.

6) The sentence "I was last sorry for a person when he had an incident with his motorbike" contains a mistake. It should be "I was last sorry for a friend of mine when he had a motorbike accident."

7) The sentence "Have you ever blamed a friend for something he/she didn't do? Yes, I have. I blamed my best friend for forgetting our meeting" is grammatically correct and doesn't require any changes.

8) The sentence "I got angry with her, but she was really sorry for it. So I decided to apologize to her" is grammatically correct and doesn't require any changes.