Writeacher, I changed my name to Mike1 because someone answered my post with "I don't know". I hope it is OK with you.

Here are the sentences I left out before.
1) I was proud of myself for helping my granny last holiday (on my last holiday, during my last holiday?)
2) Last year I thought that my friend Sam had broken my bike. I blamed him for breaking it for one month.
3) I depend on my parents. I think I will depend on my parents until I find a job.
Last year my football friend Richard's father (the father of a my friend ..) died. I felt very sorry for him and his family.
4)I last felt sorry when my friend Mary / I last felt sorry for my friend Mary when she ..
Are both possible?
She lost her mobile phone last summer. She was really upset, but fortunately her parents didn't blame her because it wasn't her fault.

Just ignore people who post like that. I come in later and delete those nonsense posts.

1 - OK

2 - This reads that Sam kept breaking the bike for a month!! (Move "for one month" to the beginning of that sentence.)

3 - Last year, the father of my football friend Richard died.

4 - Yes, both are OK.

All else is fine.

Or ... even better:

3 - Last year, the father of Richard, my football friend, died.

1) The correct preposition to use in this sentence depends on the intended meaning.

- If you helped your granny at some point during your last holiday, you can say, "I was proud of myself for helping my granny during my last holiday."
- If you helped your granny on the specific day of your last holiday, you can say, "I was proud of myself for helping my granny on my last holiday."

2) The sentence is grammatically correct. However, if you want to make it clearer, you can rephrase it as, "Last year, I thought my friend Sam had broken my bike, so I blamed him for one month."

3) The sentence is grammatically correct. However, if you want to improve the flow, you can rephrase it as, "I depend on my parents, and I think I will continue to do so until I find a job."

4) Both phrases are grammatically correct, but they have slightly different meanings:
- "I last felt sorry when my friend Mary" implies that this was the most recent time you felt sorry.
- "I last felt sorry for my friend Mary when she" implies that this was the most recent time you felt sorry specifically for Mary.

Regarding the last sentence, it is grammatically correct and conveys the intended meaning.