To equip translators with the abilities to detect and correct errors is one of the major objectives of a translation course. A translator who has the criteria knows where a mistake might take place, how to avoid it, and to ask for help. This paper tries to examine translation errors from different aspects: referential meaning, specificational meaning, relational meaning, collocation, diction, variety, mood, style, ambiguity, figurative meaning, tone, language interference, etc. This is a preliminary study to set up criteria for translation. The results of our analysis, which show students do's and don't's, are themselves valuable teaching materials.