In einem im 'Spiegel...(veröffentlichen) Bericht heißt es, dass die Eltern,...(Artikel) Kinder zweisprachig aufwachsen,...(hoch) Ansprüche an...(their) Kinder...(haben), als die Lehrer,...(Artikel)...(pronoun for Kinder) unterrichteten.

Firstly, I would go through each stage of the sentence with the student. They must write each verb, noun or pronoun in the correct case and tense with the correct endings. At each step I would expect not only the answer, but a short explanation of how they arrived at it (ie. a grammatical explanation). The full correct sentence is as follows: