1) earlier or before I'm expected to. Include the phrase to clarify.
2) with his left foot
6) IT is not the same.
1) Can't you say:
Would you mind if I stopped working ten minutes earlier (than I'm expected to)? (If I write "before" or earlier without including a phrase is it a mistake??)
It's not a mistake, but it leaves the idea incomplete. To be clear in your speech and writing, you need to be as complete as possible, not leaving any listener or reader waiting for the rest of the information.
2) I broke a glass and I blamed my friend. Since then we are not (why not "have not been"?) friends any more.
You can use either "have not been" or "are not" -- both mean that you were friends, but no longer are friends.
2) I felt sorry for a friend who twisted his ankle. He's going to have problems with his left foot.
Use "that" for things; use "who" for people.
3) I last felt ashamed when I blamed my friend (better a friend) even if he hadn't done anything wrong. Shouldn't I use the past parfect "hadn't done", instead of "didn't do"?
Either one works, but "hadn't" is probably better.
4) She congratulated Mark for/on passing his exam (because he passed/had passed his exam) with the highest mark. (Are all alternatives possible??)
All are possible, yes.
5) He is enthusiastic about his exam result (is it possible?). He is satisfied, delighted, pleased, content WITH (not about) his exam result. But He is happy about/with his exam result. He is cheerful about his exam result.
I'd say "exam results" even if it's only one exam, but yes, all are possible.
6) Do you "ever" prepare breakfast by yourself? Is not the same as Do you "always" prepare breakfast by yourself?
They're not quite the same, but they're close. The first asks if someone has ever done this (even once). The second is asking if he does this all the time.
English - I still have a few doubts on sentences you checked yesterday. 1) I did...
English - Thank you. I still have a few doubts. So both sentences are correct: 1...
English - I still have a few more doubts. 1) Thank you for being so quick in ...
English - I still have a few doubts on the use of to/at/in after have been. ...
English - I still have a few more doubts. Could you check the following phrases ...
English - I have a few more doubts. Thank you. 1) I keep fit by doing exercise ...
English - I still have a few doubts. Thank you very much for helping me. 1) I'm ...
Business Communication - Which way of asking for action carries the highest ...
English - I still have a few doubts. I hope you can have a look at them, too 1)...
English - I still have some doubts and a few sentences to check I can't ...