Think of one word only which can be used appropriately in all three sentences.

Thank you for your last letter. It was great to hear from you.

This is a quick note about one event. My school organised a Word Food day, so I and my classmates could taste different meals from around the world.

Students prepared a lot of various dishes. They brought a couple of pizzas and pastas, some sushi and paella, a cheesecake, a pudding and much more. I prepared a delicious beef stew and an apple strudel.

I tasted all that dishes and I really liked sushi. It's yummy! Sushi is low-fat, healthy and authentic. I adore that!

I liked that event very much! I ate very interesting meals which I'd hardly ever taste. I'd go again to this action.

Anyway, what's going on with you? It'd be great to hear some news.

Hope to see you soon.бъяснение:

I have just been  to the post office. I've got some stamps.

Your computer will work perfectly if you call out a technician to repair it. 

The modern operational system controls and manages the use of the hardware.
The use of the hardware by the modern operational system.(Вот здесь не поняла что нужно дополнить)

We have to apply for a visa. We can't just travel on our passports.

will be helped 

My parents will go to the South next year.

Have they been in touch yet? – No, they haven't. I had had any news. (если честно не поняла смысла этого предложения)

I often drive to work but I take the train this morning because my car is in for repair. 

will Peter ride his bicycle this afternoon? Can I borrow it? 

We were not able to get a hotel room because we did not book in advance.