"벨기에 사람의 어머니는 스페인인입니다."
Translation:The Belgian person's mother is Spanish.
Throughout the course, most sentences' translations don't have 'the'. However, there are many cases we cannot just omit '그' in Korean. For example, in this sentence, it sounds so awkward because it sounds like 'All belgian people are born by spanish' and it's not true. It should include '그' or whatever else to clarify