A. 1. Check your Trash in Google Calendar: Open Google Calendar on a web browser, click on 'Trash' in the left sidebar to see if the deleted events are there. You can restore them if found. 2. Ensure you are not accidentally deleting events by tapping the wrong option. Be cautious when using the delete function.

B. 1. Consider using the 'Undo' option immediately after an accidental deletion. 2. Regularly back up your calendar events by exporting them to a file: Open Google Calendar on a web browser, go to 'Settings' > 'Import & export' > 'Export'.