Зависит ли подъёмная сила стратостата от времени суток? ответ поясните

1. He gave up smoking last month.
2. They were in Moscow last week.
3. My friend made an interesting journey last summer.
4. These people came here a minute ago.
5. Liza spent three weeks in the country last year.
6. He gave me an interesting book to read yesterday.
7. I took a lot of beautiful pictures some minutes ago.
8. An important meeting took place here tow das ago.
9. He wrote this letter last week.
10. They saw wax models in Madame Tussaud's museum some days ago.