Schreiben Sie einen Brief an ihren/ihrer Deutsch Lehrer/Lehrerin, und erzählen Sie was Ihnen am Sprachunterricht gefallen hat und weshalb er so effizient war. (from past IB exam)

Although I will not be answering this question, I will point out important things to consider when posed with a question as such in the final exam. Firstly, it is essential to establish what format of text the question/statement is demanding. In the case above, a letter is to be written to the german teacher. It is important to follow the given format of the question/statement, as points are awarded for doing so. Therefore, I recommend starting the answer by writing "Liebe/Lieber Frau/Herr...," to introduce the idea that a letter is being written. Then, one can proceed by mentioning what one liked about the class and why it was effective/how it helped in learning. This should be roughly 250-350 words. The letter should then finish with "Liebe Grüße, ...." or something along those lines, to indicate the letter is completed.