Thank you for noticing and for creating a discussion. Are you familiar with the report function during lessons? After answering a question, a report button will appear. Under that button are several options such as: "My answer should be accepted"; "The audio doesn't sound right"; "The English/Foreign sentence is unnatural"; and an open field in case the problem doesn't fit any of the given descriptions. If you come across any more mistakes, could you try reporting them in this way? This will help staff members to recognise the questions that are causing problems. Thank you for taking the time to report errors as it will help improve everybody's learning experience.

I am using the English to Spanish lessons on the iPhone App, and there does not appear to be a "report function" on the App (most likely, a real-estate limitation). In the "Nature" exercise there is a Translate this sentence question : "The sheet". And the correct answer is "La hoja". The error here would appear to be that the question should read "The leaf" rather than "The sheet"