Make the Ctrl+Shift shortcut for iBus to switch input

I am always familiar with using Ctrl + Shift to switch between input modes (switch typing language).

The setting in ibus-setup cannot let me choose this setting (or this very likely is my fault).

After reading this thread: https://forum.kde.org/viewtopic.php?f=17&t=162008.

All I have to do is run this command as my normal user and everything is fine now:

gsettings set org.freedesktop.ibus.general.hotkey triggers "['<Control>Shift_L']"

I personally thank FireHeadMan for his/her answer above.