39、Empty the trash even if told you can’t(强制清空回收站)
open a terminal window and type the following two ,

    sudo rm -rf ~/.local/share/Trash/{files,info}/

40、Login automatically after boot-up(自动登入系统)
click System ! Administration ! Login Window. Then click the Security tab, and put a check in Enable Automatic Login. From the User dropdown list, select your username. Then click Close