Learn Danish: Hvem køber skabet? - Who buys the cabinet?

In Danish, you don't use a separate word for "the". Instead, you attach the article to the end of the noun. Because "a cabinet" is an et word (et skab), you add -et to the end to say "the cabinet" (skabet). If it were an en word, you would add -en.

This lesson is about plurals ending in -e. How would I say "Who buys cabinets?"

You would take the base word skab (cabinet) and add the -e ending to make it plural: skabe. The sentence would then be Hvem køber skabe?

Does køber mean "buys" or "is buying"?

It means both! Danish doesn't have a separate "-ing" tense (present continuous) like English does. Hvem køber skabet? can mean "Who buys the cabinet?" as a general fact, or "Who is buying the cabinet?" right at this moment.

Why doesn't the verb køber change depending on who is doing the buying?

Danish verbs are very simple because they do not change based on the subject (the person or thing doing the action). Whether it is "I buy" (jeg køber), "he buys" (han køber), or "who buys" (hvem køber), the present tense verb always ends in -r.