1) Four American 17-year-old students will be in class with us tomorrow for an hour.

2) I need to prepare some activities to entertain them. They can't speak any Italian so the activities must be English.
3) I was thinking of preparing a questionnaire myself about their families and habits, which I will hand out to my students.
4) The four American students will be asked to move around the class and answer the questions selected by the Italian students.
5) The Italian students will have to notice their answers and be able to report them to the class. The winning student will be the one who is able to report the most answers. What do you think?
6)Our town is twinned with (??) this American town and that's why our students are asked to put up these American students for three weeks.

In my next post I will let you have a look at the questions I prepared. Can you help me improve my questionnaire? Thank you very much.

All these sentences are fine. The only thing needed is a comma after "town" in the 6th sentence.

Of course! I would be happy to help you improve your questionnaire. Please provide me with the questions you have prepared, and I will offer suggestions and feedback to make them even better.

Before we begin, it's great that you're looking for activities to entertain your American visitors and that you are focusing on English-based activities since they can't speak any Italian. Hosting the questionnaire activity seems like a fun way for your students to interact with the American students and practice their English skills.

Now, let's take a look at your questions and see how we can improve them. Please share your questionnaire with me.