I can't find "file open" in the menu

The file menu has these sub items:
Template, reload, versions, save all, export, export as PDF, send, preview in web browser, print, print preview, print settings, properties, digital signatures, exit Libreoffice.
Some useful items missing are Open, New, recent documents, close …
What’s happened? The file menu of Calc is workingOK
the version is 5.1.2.2. running under Gnome Ubuntu
I have just reloaded the entire program from Synaptic, and no change

I have no idea why I ended up with this situation, but I managed to get out. I opened the folder /Home /.config and deleted the folder /libreoffice. Problem solved.