Not sure if this is the place to make suggestions about how to improve this page but I wanted to make a comment.
The practice questions for this grammar lesson are to give the translation in english for some sentences given in french.
I don't find this particularly helpful as it is not testing my knowledge of the grammar point 'de' in a negative sentence. It would be better if the sentence in the question was given in english and the learner had to click on the correct option in french (as is normally the type of practice question given for other grammar lessons)
Thank you!