In Swahili, it's not indicated at all. There are cases where English really loves to use possessives, such as "How was your day?" In Swahili, you don't use "your" here but it's really weird in English without it. You wouldn't say "How was the day?" most of the time.
The course is sometimes a bit literal and sometimes a bit more idiomatic, but most of the time, when one thing is allowed but not another, it's because the course was rushed to come out early and they haven't added all the various alternative possible answers that there should be ... which can be a big job because for some sentences, there can be about fifty possible translations.
Anyway, if anything like this comes up again, use the report feature.