Translation:Seventh day, seven o'clock, seventh seat
This is what I mean by Duolingo being useless. I wrote "the seventh day, the seventh hour, the seventh seat." The program responded: You used the wrong word. Seventh day, seventh hour, seventh seat It did not say "o'clock." In fact, both interpretations are perfectly correct. "Сьома година після польота" would mean "the seventh hour after the flight," not "seven o'clock." This program is too bloody frustrating to work with.
I agree that this exercise is likely the nadir of the course. It's little more than a bunch of meaningless words (not even sentences). Sadly, designers of language courses sometimes feel that the tasks are too easy and so are tempted to make you think (as in exercises where you have to do arithmetic or remember what city is the capital of what country), forgetting that fluency comes only when you stop thinking.