Sometime I push the wrong keyword, or delete without intention, and how can undelete this action?
Does Edit/Undo (Ctrl-Z) not work for you?
no, only undelete the last word
The Undo stacks are necessarily created separately for various parts of the interface, so you’ll want to make sure that your focus is in the area where you need to undo before trying Ctrl+Z (Edit > Undo). For instance, if you type something in the index card in the inspector and then, while the focus is there, use Undo, your typing changes there will be undone. If you type in the index card and then click into the editor before using Undo, it will undo your last typing in the editor, not in the index card.
fine detail, I will try.