Could you please check the following sentences, please? Thank you.

1)I'm still waiting to receive an answer from the principal of the German school to see if they are willing to accept your school in our Comenius partership.
2) In any case, our science teachers are really interested in developing European projects with your school in the near future.
3) So, why don't we start with an e-mail partnership among our students which could eventually lead to a school exchange (programme)?
4) My students from the eleventh class (about 17 years old) are enthusiastic about the idea of corresponding with Finnish students in English.
5) Do you think you could involve some of your students from the international branch?

3. omit comma

All else is fine.

Sure! Here are the corrections for the sentences:

1) "I'm still awaiting a response from the principal of the German school to see if they are willing to accept your school into our Comenius partnership."

To get the answer, you can send an email or make a phone call to the principal of the German school and ask about their decision regarding your school's participation in the Comenius partnership.

2) "Regardless, our science teachers are very interested in developing European projects with your school in the near future."

To get confirmation or discuss further details, you can send an email to the science teachers of the German school expressing your interest in collaborating on European projects.

3) "So, why don't we start with an email partnership among our students, which could potentially lead to a school exchange program?"

To initiate an email partnership, you can write a formal email to the concerned teachers or coordinators of the German school proposing the idea of starting an email exchange program involving students from both schools. In the email, you can outline the objectives and potential benefits of the program.

4) "My students in the eleventh grade (approximately 17 years old) are enthusiastic about corresponding with Finnish students in English."

To involve Finnish students in the correspondence, you can reach out to the teachers or coordinators of a Finnish school that you wish to collaborate with. You can introduce your eleventh-grade students and their interest in corresponding with Finnish students. You can propose English as the language of communication and discuss the possibility of starting a letter exchange or online communication between the two groups of students.

5) "Do you think you could involve some of your students from the international branch?"

To involve students from the international branch of the German school, you can inquire directly with the concerned teachers or coordinators of the international branch. Send them an email or set up a meeting to discuss your idea of involving their students in the activities or partnerships you wish to establish.