No problem! Here are the revised sentences and their explanations:
1) The astronaut on the space station saw a sunrise every 90 minutes because the station orbits the Earth 16 times a day. This means that every time the station completes a full orbit, 90 minutes have passed and a new day begins for the astronomer. During his time in space, he not only observed the stunning sunrises but also conducted important experiments and took numerous photos.
2) Unfortunately, the astronaut experienced a mishap when he lost his camera in space. It happened when the camera floated out of his pocket and disappeared. Losing belongings in space is a challenging situation since objects continue to float freely due to microgravity.
3) Space City functions as a training site for astronauts preparing for space missions. It resembles a small town, complete with amenities such as a secondary school, hospitals, and sports facilities. Astronauts undergo rigorous training at Space City to equip them with the necessary skills and knowledge for their missions.
4) The question "What are you going to wear at/for/to the party?" asks about the appropriate preposition to use in this context. While all the options can be used, "to" and "for" are more commonly used. "At" could also be viable, but it may imply a more specific location within the party. For example, "What are you going to wear at the party?" could refer to what you plan to wear at the dance floor or a specific area of the party.
5) I suggest taking our American host students to Genoa. This recommendation entails arranging a trip or excursion to the city of Genoa for the students. Genoa is a picturesque city in Italy that offers various attractions and cultural experiences.
6) I propose that they start their day by visiting the beach in the morning and after that, head to the aquarium for a visit. In the afternoon, they can go shopping for souvenirs. This itinerary allows them to enjoy the beach and marine life in the morning, followed by shopping in the afternoon, ensuring a well-rounded and enjoyable day.
7) I suggest that the school hires a coach for the day, with the intention of the school paying for the coach expenses. Additionally, the students will need approximately £15 for food throughout the day and an extra £10 for spending money. This proposition ensures that transportation is taken care of, and the students have enough money for their meals and personal expenses.