Впредложении нужно время определить, отрицательным сделать и вопросительным. we went about the city in a bus and got out only to have lunch at mcdonalds.

Это Past Simple.
We didn't go about the city in a bus and get out only to have lunch at McDonalds.
Did we go about the city in a bus and get out only to have lunch at McDonalds?

We went about the city in a bus and got out only to have lunch at McDonald's.
We did not go about the city in a bus and got out only to have lunch at McDonald's.
Did you go about the city in a bus and got out only to have lunch at McDonald's?

1. 1. Лектор привел несколько примеров международных связей севастопольских ученых.
examples - б) признак множественного числа имени существительного;
scientists' - в) показатель притяжательного падежа имени существительного 
ties -  б) признак множественного числа имени существительного;
2. Основание Севастополя датируется 1783 годом.
dates - а) показатель 3-го лица единственного числа глагола в Present Indefinite;
3. Автор упоминает это явление в своей статье.
mentions - а) показатель 3-го лица единственного числа глагола в Present Indefinite;

Dear John.

Thank you for your letter I was glad to get it. You have asked me about what kind of sport I like. Well, my favourite sport is swimming. When i was child, i can remeber one occasion when one girl was swimming in the poll and accidently started to sink there. In that moment one man save her with his abilities and skills from swimming. I was enspired with his action and start swimming. To be honest, i would like to do a sport rather than watching. Because swmming is not visual sport where you can find mistakes, yet this sport is only with practicing and improving your phsical skills as your football. Actually, I'm agree with you that doing sport is better than watching it. If you haven't practice you've never had a result from it.

Looking forward to hearing from you.

Best, (Ваше имя).