Sorry, The problem is solved. Please ignore the above questions.
"sudo apt-get install fonts-noto-cjk"
"sudo apt-get remove fonts-noto-cjk"
opera-stable_39.0.2256.48_amd64 on Ubuntu 16.04.1, and found out that all Chinese character are invisible. The following are screen captures:
Looks like your connection to Opera forums was lost, please wait while we try to reconnect.