Конечно! Давайте преобразуем каждое из предложений в прошедшее время, добавив нужное обстоятельство времени к одному из них.
My working day lasts eight hours.
- My working day lasted eight hours.
Do you often get letters from your friends?
- Did you often get letters from your friends?
Does he do well in French?
- Did he do well in French?
We discuss a lot of questions.
- We discussed a lot of questions yesterday. (Обстоятельство времени: "yesterday")
They don't often stay at the factory after six o'clock.
- They didn't often stay at the factory after six o'clock.
Теперь все предложения преобразованы в прошедшее время, и к одному из них добавлено обстоятельство времени для большей ясности.