"The customer buys the shoes."
Translation:Emptor calceos emit.
In my opinion cliens (which has been introduced in the course) corresponds better to the English word customer than emptor, which literally is a buyer. Duo did not accept it, and I reported it along with its other five syntactical variations (calceos cliens emit etc.).
Did you see that in a multiple choice task? Besides being illogical, it is not a possible answer since emptor is singular and coquunt is plural. They do this to make it easy for us to spot the correct answer. In my opinion, at least at higher crown levels they should make the distractors more difficult, less obviously wrong.