alternative signs

Sometimes alternative signs are provided when introducing a new word, but not always. But then when questions are asked in the exam, an alternative sign is used that was never taught. The two examples so far have been breakfast and lunch. The words for breakfast and lunch are taught, but then in an exam, the alternative of time frame and meal are used instead. Like “morning meal” signs are used instead of breakfast. Or “noon meal” is used instead of lunch. But we are supposed to use the translation as breakfast and lunch in our response. It is intuithve so not a big deal, but still should be part of the education that either approach can be used to sign the type of meal.