How to use scim to type Chinese characters under English environment?

Just open /etc/environment and add another line in it:

LC_CTYPE="zh_CN.UTF-8"

after

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
LANG="zh_CN.UTF-8"
LANGUAGE="zh_CN:zh:en_US:en"

Beware of the symbols used, it's LC_CTYPE="zh_CN.UTF-8", not LC_CTYPE=“zh_CN.UTF-8“ as mentioned in http://www.oklinux.cn/html/Basic/jyjq/20080323/49865.html

So the new /etc/environment will be

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
LANG="zh_CN.UTF-8"
LANGUAGE="zh_CN:zh:en_US:en"
LC_CTYPE="zh_CN.UTF-8"