404. That’s an error.

The requested URL /translate_c?hl=zh-TW&sl=en&u=http://en.wikipedia.org/wiki/Operations_research&prev=/search%3Fq%3Drussell%2Backoff%26hl%3Dzh-TW%26rls%3Dgm%26sourceid%3Dgmail&rurl=translate.google.com&twu=1&usg=ALkJrhgYoK3aGXqYOgBADw3sWzK7j9cI9g was not found on this server. That’s all we know.