解決方法：
flashmx@ubuntu:~$ cvt 1920 1080 # 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync flashmx@ubuntu:~$ xrandr --newmode "1920X1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync flashmx@ubuntu:~$ xrandr --addmode Virtual1 "1920X1080_60.00" flashmx@ubuntu:~$ xrandr --output Virtual1 --mode "1920X1080_60.00"
親測真實有效。
If the last command doesn't work for you,you can go back to ubuntu display gui setting and can chose the display you have added just now.For me the option was 1904 x 1070 (16:9)
However if you are fine with this experiment and have found the desired screen resolution and to make that permanent,write the all the last 3 commands starting from xrandr --newmode command in your .xprofile file using following command and then save,exit and restart your ubuntu vm and you will get your desired resolution permanently.
（如果上一個命令不為你工作，你可以回到Ubuntu顯示界面設置，可以選擇你剛才添加的顯示。我選擇1904×1070（16:9）
但是如果你是好的這個實驗和發現所需的屏幕分辨率，使永久的，寫的所有的最后3個命令從xrandr --在你的指揮方式。xprofile文件使用下面的命令，然后保存，退出並重新啟動你的Ubuntu的虛擬機，你會得到你想要的分辨率永久。）
$ gedit ~/.xprofile