Sorry for bothering everyone! Please help.
I wrongly used the git rebase --hard and overwrite all local files. Then I use git reflog and git reset --hard but did not find the former version! I searched for many questions but it seems that they only deal with git rebase without --hard.
How could I find the deleted files! Thanks!
I checked again and found that I used git pull --rebase. Sorry for misunderstanding.
Command sequences:
git stash -> git pull --rebase -> git reset --hard with id (failed) -> git stash apply (succeed)
If you did not use stash to take snapshots before the reset --hard, there is unfortunately nothing you can do to restore your lost working tree.