Go to Window-Preferences-General-Keys from eclipse
When you find Content Assist, you will find that the shortcut key is "ctrl+space", which conflicts with the default shortcut key for switching between Chinese and English input methods of the Windows system. It needs to be modified and changed to "alt+/", but it is still invalid. Looking for other shortcut keys that also use "alt+/", found it, called "word completion", and now change its shortcut key to something else! For example "alt+c", test again, OK!