Help & Sorry 4 poor English.

I am bad at using Ubuntu.

This is copied in settings.

There was a keyboard-sign on the right-up of the screen.

There was sogou-input in the computer.

I was able 2 input Chinese a few minutes ago. But after I clicked something on the keyboard-sign by accident, the sign disappeared.

Now there is only a forbidden-sign at the position where the keyboard-sign was, as the picture below.