Ubuntu18.04 has been released, but Sogou input method is not yet supported.
The Chinese input method that comes with 18.04 selects sunpinyin as the default Chinese input engine, but does not put sunpinyin in the iso image. For details, please refer to https://forum.ubuntu.com.cn/viewtopic.php?f=49&t=486960&start=8 and http://forum.ubuntu.org.cn/viewtopic.php?t=486960
Just change the default input method to intelligent pinyin
The specific operation steps are given below (for novices like me)
1. Click Settings to enter the settings interface
2. In the language option, click Manage Installed Language. It needs to be installed for the first time.
3. Add the Chinese package, click Install/Remove Languages, check Chinese Simplified in the pop-up window, click Apply to continue installing the Chinese package, and IBus is still selected for the Keyboard Input method system.
4. After the Chinese package is installed, go back to the language setting interface to add input options
Select Chinese (if you don't click Other to find or search in it), you can see related options (pinyin, Wubi) at this time, select Intlligent Pinyin
5. If you are not used to the way of language switching, you can change the shortcut in Devices>Keyboard, and change the original default win+space to ctl+space